Monthly Archives

January 2019

Divorcing Penguins – Not All Penguins Stay Together for Life

king penguin

Divorcing Penguins – Not All Penguins Stay Together for Life

by Nataly H. Aranzamendi

Penguins are frequently portrayed as examples of fidelity and representatives of long-term relationships. Let’s discover how much of that is true.

Understanding monogamy in birds

Monogamous birds are those that choose one partner to breed and to raise their offspring with. As with humans, scientists have discovered that some birds can be “serial monogamists” and that they engage in new relationships after the death of their partner or by “divorce.”

Thanks to techniques that allow scientists to mark birds and follow them throughout their lives, they have discovered that not all birds mate for life and many of them divorce. Divorce in birds is confirmed when at least one bird of a “couple” re-pairs with another individual and when both former partners are still alive1.

Divorce rates in birds vary widely between and within species1 and penguins are not an exception. Mate fidelity in penguins is about 72% on average, with such rates ranging from 29% to 97% (measured for 12 species)2. Divorce accounts for 13% to 39% of this percentage of mate change.

 

 

 

 

A Yellow-eyed Penguin heading to its nest.

Scientists are trying to understand bird divorce

Scientists have been trying to understand the reasons for divorce in birds for decades, but this has been logistically challenging. Penguins, for example, are long-lived and travel considerable distances after breeding, making it hard to follow them throughout their lives.

One important detail is that annual survival of individuals needs to be known with high certainty. Otherwise, we would erroneously assign a separation, when in reality one member of the pair did not survive. “True survival” can only be assessed if penguins return to the same spot where they were first captured. So not finding them in the same place could be because they skipped breeding or simply decided to go elsewhere. Despite all the challenges to know “true survival” and divorce rates, scientists have managed to collect considerable data in divorcing birds.

So why do birds separate from their mate?

 

 

 

Photo source: Hannes Grobe/AWI, Creative Commons Attribution 3.0

The benefits of staying with the same partner can be multiple. More familiarity in a relationship can make birds better at protecting their nests. Pairs can improve coordination and breeding performance, meaning that they can get better at protecting their chicks after learning from bad experiences1.

However, in species when partners separate after breeding, reuniting year after year can often be a difficult process. When the costs of reuniting are high, it is likely that birds will opt for new partners.

Scientists have agreed that in order to divorce, benefits should exceed costs for at least one of the birds. The most common causes of divorce besides physical separation include bad reproductive performance and a partner with a low quality territory1.

It is expected then to find “improvements” when comparing former and new partners. The new partner will be considered more compatible if the pair produces more offspring than before or if the new partner has a better territory. It is also possible that not only one but both divorcing birds find better options after a separation1.

In the penguin world, King and Emperor penguins have the highest rates of divorce, with more than 80% of King Penguins changing partners between breeding seasons. The main reasons for change were asynchrony in arrival and large access to new mates each breeding season3.

Approximately 40% of Adelie Penguins changed partners in two consecutive breeding seasons due to divorce and/or death. In contrast, Gentoo, Galapagos, Little, Magellanic and Yellow-eyed penguins have high rates of mate fidelity, with more than 80% of individuals on average breeding with the same partner in two consecutive years2.

Something that has puzzled scientists is that they have compared the reproductive success of penguins between former and new partners for some species and they have found no apparent increase in reproductive performance2. Nevertheless, we have learned so far that divorce is a complex issue for birds, possibly as complex to understand as it is in humans, and it could be triggered by multiple causes. Thus, consequences can be only measured in the long-term.

Only the continuation of long-term studies, i.e. following individuals for several years, will portray the whole picture of the reasons why divorce is a beneficial strategy in the avian world. This will help scientists to fully understand a phenomenon that seems to be widespread in birds.

Did you think penguins were married forever? Or would they get divorced? Let us know your thoughts!

Also read some other blogs about penguin life:

References:

Choudhury, S. (1995). Divorce in birds: a review of the hypotheses. Animal Behaviour, 50(2), 413-429.
Williams, T. D. (1996). Mate fidelity in penguins, pp 268-285. Black, J. M. (Ed.). (1996). Partnerships in birds: The study of monogamy: The study of monogamy. Oxford University Press, UK.
Olsson, O. (1998). Divorce in king penguins: asynchrony, expensive fat storing and ideal free mate choice. Oikos, 574-581.

Chinstrap Penguins in a Warming World

Chinstrap Penguins

Chinstrap Penguins in a Warming World

by Nataly H. Aranzamendi

A warming planet is changing the environment that animals used to know, let’s explore what is changing for Chinstrap Penguins.

The food that Chinstrap Penguins prefer is harder for them to find.

Krill-Eating Penguins

Chinstrap Penguins live around the Antarctic Circle. They can breed in Antarctica, Bouvet Island, the French Southern Territories, and South Georgia and the South Sandwich Islands1. Their diet mainly consists of fish, krill, shrimp and squid for which they regularly swim up to 80 Km to obtain1.

A recent study found that when ocean conditions change, Chinstrap Penguins might have to travel farther and spend more effort to get their favorite prey2.

Chinstrap Penguins depend heavily on Antarctic krill, as other animals in Antarctica do. Krill are small crustaceans found in all the world’s oceans. In the Southern Ocean, the Antarctic krill is the most abundant species and is a key resource and a keystone species in these ecosystems3. The dependence of Chinstrap Penguins on krill is particularly relevant during the breeding season.

Small swarms of krill can aggregate around coastal and shelf areas, while large swarms are more likely to be found at sea. Sometimes, when wind currents change drastically, it creates very poor conditions for krill to feed (e.g. less availability of phytoplankton) and the krill must dissipate from small coastal aggregations, thereby becoming a sparse or even absent resource in these areas2.

Recent studies have found that climate change will bring an increase in frequency of El Niño events. But not only will those events increase in frequency, upcoming El Niños are likely going to be stronger than before, and are going to be associated with extreme weather events4, such as warm waters and variable wind currents. Variable wind currents have the potential to make krill distributions unpredictable.

Chinstrap Penguins are now traveling farther to find their food.

The distances that adult Chinstrap Penguins traveled from nest to foraging sites were measured during two breeding seasons in 2014 and 2016, in breeding colonies located at the Powell Island in the South Orkney Islands archipelago. Both breeding seasons were characterized by different environmental conditions. In 2016, an unexpected short-lived El Niño occurred provoking coastal down-welling and reducing coastal krill availability2.

Adult Chinstrap Penguins in 2016 had to travel farther and stayed at sea longer on each trip. The 2016 penguins also had to cover larger areas at sea on each trip. Normally, when penguins forage for krill, they prefer to do so in coastal waters, where small swarms are aggregated in dense packs. Penguins remain in these high density patches until those patches are depleted. Since strong wind currents make krill less aggregated, penguins have to travel farther for food.

Penguins normally travel far if they need to, but the energetic consequences of moving longer distances than usual are still not known. There is also another constraint. When chicks are out of the nest at the crèches, adult penguins are limited by the amount of time they can spend away and sometimes are forced to come back before they’ve finished foraging enough prey for themselves and their chicks.

Some adult penguins tracked in 2016 traveled between three to 10 times the maximum distances measured in 2014. Although the consequences of such differences were not measured in this population, the authors of the study suggest that such a shift in behavior could potentially cause nest desertions and increase chick mortality.

There is another factor that might represent increasing pressure for Chinstrap Penguins and other Antarctic wildlife: the commercial exploitation of Antarctic krill.

Antarctic krill has been always considered an abundant resource and has been heavily exploited in the past. Thanks to regulations implemented in the last decades there has been a rebound in krill abundance, to which some fisheries have responded increasing their quota. Krill fisheries prefer southern waters because, just as for the penguins, the fisheries can find swarms of krill grouped in a more predictably way3.

Impacts of fisheries and climate change are still unknown.

A Chinstrap Penguin taking a break after a long day of fishing.

The impact that the exploitation by fisheries and climate change combined will have on krill availability is still unknown but could be catastrophic for all wildlife in the Southern Oceans.

Luckily for some species, it was recently announced that krill fishing companies operating in Antarctica will stop operations in buffer zones close to breeding colonies of penguins from 2020 onwards3. This could alleviate the pressure coming from the fisheries industry, however we still have not found an accurate way to predict the impact of changing climatic conditions on the survival of this species. Whatever happens next for Chinstrap Penguins will have to be seen in the upcoming years.

What a diet these penguins have! Did you know about this? Let us know what you think.

Also check out some of the other blogs we have:

References:

https://en.wikipedia.org/wiki/Chinstrap_penguin
Lowther, A. D., Trathan, P., Tarroux, A., Lydersen, C., Kovacs, K. M., & Handling editor: Howard Browman. (2018). The relationship between coastal weather and foraging behaviour of chinstrap penguins, Pygoscelis antarctica. ICES Journal of Marine Science, 75(6), 1940-1948.
https://en.wikipedia.org/wiki/Krill#Human_uses
Cai, W., Wang, G., Dewitte, B., Wu, L., Santoso, A., Takahashi, K., … McPhaden, M. J. (2018). Increased variability of eastern Pacific El Niño under greenhouse warming. Nature, 564(7735), 201–206. https://doi.org/10.1038/s41586-018-0776-9

The Journey of the Little Penguin

Little Penguin

The Journey of the Little Penguin

by Nataly H. Aranzamendi

The Little Penguin is the smallest species of penguin, weighing only one kilogram (2.2 pounds) and ~33 cm (13 inches) tall. Every year during the reproductive season, parents engage on daily journeys to find food for their newborns, and their adventures are witnessed by ecotourists at nature parks that protect the delicate habitat of these native birds.

We sat at dusk waiting for the last rays of sun to fade away. The audience was impatient, with whispers going around like a wave. The scene finally became completely dark and we could barely distinguish the horizon. It was an unknown wait, without knowing what to expect or where to look. Suddenly, tiny silhouettes appeared on the horizon. It was the beginning of an amazing night. It was the start of the penguin parade.

I visited Phillip Island in Australia in 2013 for the first time and I was tremendously excited to see this so-called “parade.” I had never heard something like that happening in the natural world. The people I asked gave little information. “You will have to see it yourself,” they said. Little Penguins will arrive after sunset by the hundreds, sometimes thousands. The time of the arrival could be predicted based on the activity of the day before and the time of sunset.

The total number of Little Penguins is estimated to be around 250,000 breeding pairs.

As a bird biologist, I was baffled. Was that really true? Was I expecting a synchronized parade of wild animals in front of our eyes? My doubts grew bigger when I saw the theater-like scenario where people sat. Turns out the rumors were true. Hundreds of Little Penguins marched that night in front of my eyes, all in a “coordinated” feeding parade, running through the crevices under us and rushing to deliver food to their babies.

Phillip Island is located in the south-southeast of Melbourne, Australia and it holds one of the most important colonies of Little Penguins with around 30,000 individuals1. The total number of Little Penguins is calculated to be 250,000 pairs and luckily this species is not threatened by extinction. In general, their numbers have remained stable on recent decades2.

Little Penguins’ favorite food is anchovy and they can rely on it year-round3, especially when they have to feed their offspring. However, the percentage of anchovy that Little penguins eat varies throughout the year3 and recently it has been discovered that they also rely on alternative foods, as they can complement their diet with gelatinous plankton4 and even jellyfish5.

Location of Phillip Island
Location of Phillip Island

Fortunately, Little Penguin populations are stable. But they are still impacted by humans.

Even though their numbers are relatively stable, Little penguins have not escaped the impact of humans. Because these animals live very close to human settlements, they are threatened by growing urbanization and the risk of losing their breeding habitat. In fact, it is likely that actual colonies hold the last few habitable places for penguins6.

As could happen with other fish eaters (including us!), Little penguins have been found with high concentrations of heavy metals in their bodies (e.g. mercury, arsenic, etc.), especially those living in colonies close to human settlements7. Sadly, Little Penguins are also victims of introduced species (e.g. foxes), plastic pollution, fishing and increasing warm water events2.

Fortunately for many populations of Little Penguins, there are many actions in place to protect them and to assure their brighter future. Several protected areas and sanctuaries in Australia and New Zealand have monitoring programs and scientific research that will continue giving us more information about them.

Management of tourists has been effective at buffering the negative impacts of human activities. Also, the management of invasive species has been fundamental to keep colonies predator-free as, for example, a single fox could cause massive damage in a breeding colony. Moreover, educational programs targeting schools and general public have been central to promote the conservation of such iconic species.

The penguin parade I saw was unforgettable. It was fantastic to watch those apparently little, but nonetheless strong, persistent parents rush back to fulfill their parental duties. I wondered if they were carrying enough food, if those babies were going to make it or if those parents were going to try again next year. Too many single stories to have an answer. Nonetheless, that night I felt optimistic, thinking that as long as they had people caring for them and a protected safe haven in Phillip Island, penguins will keep coming back in the future and more people will get to see them in this unique penguin parade.

Sources:

https://www.penguins.org.au
1 penguinfoundation.org.au
2 BirdLife International 2017. Eudyptula minor (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22697805A112478911. http://dx.doi.org/10.2305/IUCN.UK.2017-1.RLTS.T22697805A112478911.en. Downloaded on 09 November 2018.
3 Kowalczyk, N. D., Chiaradia, A., Preston, T. J., & Reina, R. D. (2015). Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird. Royal Society open science, 2(4), 140291.
4 Cavallo, C. R., Chiaradia, A., Deagle, B. E., McInnes, J., Sanchez Gomez, S., Hays, G. C., & Reina, R. D. (2018). Molecular analysis of predator scats reveals role of salps in temperate inshore food webs. Frontiers in Marine Science, 5, 381.
5 http://www.sci-news.com/biology/penguins-eating-jellyfish-gelata-05262.html
6 Rastandeh, A., Pedersen Zari, M., & Brown, D. K. (2018). Land cover change and management implications for the conservation of a seabird in an urban coastal zone under climate change. Ecological Management & Restoration, 19(2), 147-155.
7 Finger, A., Lavers, J. L., Dann, P., Kowalczyk, N. D., Scarpaci, C., Nugegoda, D., & Orbell, J. D. (2017). Metals and metalloids in Little Penguin (Eudyptula minor) prey, blood and faeces. Environmental pollution, 223, 567-574.

Penguin parade? Did you know they did that? Have you seen one? Let us know.

Be sure to read our other penguin blogs, too.

Stressed Penguins

Southern Rockhopper Penguin having a rough morning

Stressed Penguins

by Nataly H. Aranzamendi

The word “stress” has become part of our daily lives and daily vocabulary, but did you know that penguins can also get stressed? Let’s read about it:

Stress hormones in penguins

The role of hormones

Human disturbance can affect penguins and their behavior1. Penguins might simply ignore visitors and continue acting normally when humans approach but they can also react negatively by running away from our presence, staying away from their nests, or in rare cases they might react aggressively toward us or towards each other.

Aggressive or stressed reactions are triggered by internal physiological mechanisms that are mediated by hormones. Stress responses, for example, are mostly mediated by corticosterone.

Corticosterone is a hormone involved in energy regulation, immune reactions and stress responses2. Corticosterone has been largely studied in birds and the literature is vast. Some examples show that birds with increased levels of corticosterone have slower feather growth2. Other studies show that levels of corticosterone are associated with certain personality types. Corticosterone can affect birds in their early lives as it is responsible for increased begging for food in chicks and for high levels of aggressiveness2.

 

 

 

 

Ball-and-stick model of the cortisol molecule, a steroid hormone that controls the body’s response to stress.

The role of corticosterone in penguins

 

 

 

Tourists with a king penguin
Photo Source: Tourists and King Penguins at Salisbury Plain, Creative Commons Attribution-Share Alike 2.0 Generic

Corticosterone in penguins

As said before, the production of corticosterone can affect plumage quality. This is important for species that produce ornamented plumages to attract mates. The King Penguin for example produces ornamented colors when it’s time for breeding: the yellow‐orange and UV spots on its bill and yellow‐orange auricular feather patches3. Scientists found that physiological stress experiments during feather molt might affect the quality of color, in particular the production of yellow3, highlighting the possibility that ornamentation in birds is a costly physiological process.

The most well-known stress response in penguins occurs when humans visit their colonies. In a colony of Magellanic Penguins, scientists discovered that capturing penguins caused high levels of corticosterone4. However, penguins living in tourist-visited areas did not show such a strong response in comparison with penguins in isolated areas. This shows that penguins in tourist-visited areas have probably habituated to the presence of humans4. However, caution is needed when interpreting these results, as the long-term consequences of this physiological habituation are still unknown.

Corticosterone can also be involved in parental care, as it acts in combination with other hormones. In a study made in nesting Macaroni Penguins, scientists found nesting females with high levels of corticosterone5. Interestingly, those females produced heavier chicks than females with low levels of corticosterone. Thus, the authors concluded that corticosterone in this species, more than other hormones, were key for parental care5.

Stress responses change throughout a penguin’s life

Something important to remember is that responses to stress are not necessarily stable throughout an individual’s life. A study in Adelie Penguins showed that repeated handling did not affect corticosterone levels, although they found significant differences among individuals6. When the researchers extended the study for a longer period, they detected high increases in corticosterone levels, only when birds had fasted for over 50 days6. This finding highlights that stress responses are not equal at all times.

Interestingly, corticosterone is also related to personalities. As in humans, birds can have distinctive repeatable personalities. Nesting Adelie Penguins with low levels of corticosterone and with proactive personalities were more likely to be successful at times when environmental conditions were predictable. In contrast, when conditions became unpredictable, penguins showing high levels of corticosterone and reactive personalities were the more successful rearing chicks7.

 

 

Adelie Penguins in their colony

In summary, we have seen that the daily lives of penguins are governed and highly influenced by these invisible particles called hormones. One single hormone can affect the most important aspects of the life cycle of a penguin: it influences molt quality, successful reproduction, chick rearing and eventually survival.

Although corticosterone triggers an important mechanism that is useful to confront life threatening situations, like escaping or responding to a predator when being attacked, it can also have negative consequences. Corticosterone might affect early life and long-term survival, if individuals are exposed for prolonged periods of time to high levels of corticosterone. Thus, this hormone can also impact individual’s health2.

An important take home message for humans that have the opportunity to visit penguin colonies is to avoid stressing penguins by getting too close. Respect the recommended distances when visiting colonies of nesting penguins. We do not want to make penguins’ lives more stressful than normal.

Did you know penguins got stressed? Pretty much like humans. Love hearing your thoughts.

Also, read more about penguins in our other blogs:

References:

FRENCH, R. K., MULLER, C. G., CHILVERS, B. L., & BATTLEY, P. F. (2018). Behavioural consequences of human disturbance on subantarctic Yellow-eyed Penguins Megadyptes antipodes. Bird Conservation International, 1-14.
https://en.wikipedia.org/wiki/Corticosterone

Schull, Q., Robin, J. P., Dobson, F. S., Saadaoui, H., Viblanc, V. A., & Bize, P. (2018). Experimental stress during molt suggests the evolution of condition‐dependent and condition‐independent ornaments in the king penguin. Ecology and evolution, 8(2), 1084-1095.

Walker, B. G., Dee Boersma, P., & Wingfield, J. C. (2006). Habituation of adult Magellanic penguins to human visitation as expressed through behavior and corticosterone secretion. Conservation Biology, 20(1), 146-154.

Crossin, G. T., Trathan, P. N., Phillips, R. A., Gorman, K. B., Dawson, A., Sakamoto, K. Q., & Williams, T. D. (2012). Corticosterone predicts foraging behavior and parental care in macaroni penguins. The American Naturalist, 180(1), E31-E41.

Vleck, C. M., Vertalino, N., Vleck, D., & Bucher, T. L. (2000). Stress, corticosterone, and heterophil to lymphocyte ratios in free-living Adelie penguins. The condor, 102(2), 392-400.

Cockrem, J. F., Barrett, D. P., Candy, E. J., & Potter, M. A. (2009). Corticosterone responses in birds: individual variation and repeatability in Adelie penguins (Pygoscelis adeliae) and other species, and the use of power analysis to determine sample sizes. General and comparative endocrinology, 163(1-2), 158-168.

So You Want to See a Penguin

Gentoo Penguin on its egg

So You Want to See a Penguin?

by Mike King

Penguins are one of the most popular animals among wildlife enthusiasts around the world. People who want to see them in person have many options, as they are widespread all over the Southern Hemisphere and in zoos everywhere. Before one decides which method they will choose to encounter penguins, it is necessary to consider which options are beneficial to the birds—and which can be detrimental. Here you will find a brief summary of various penguin-viewing opportunities, and an easy guide to which options are best for the birds.

Viewing penguins in the wild

Penguins occur naturally on every continent in the Southern Hemisphere except continental Asia. There are many species of penguins that can be viewed on birdwatching tours, boat rides, and by anybody willing to try hard enough to find them. These encounters vary in cost depending on proximity to human civilization, which penguin species is to be viewed, and which type of organization is offering the encounter. Those who wish to visit penguins in the wild should consider whether or not human presence would be detrimental to the health of the birds.

In a study published by researchers M. R. McClung et. al., it was found that unregulated visitor access to Yellow-eyed Penguin colonies in New Zealand was resulting in a decline in penguin health and population stability. In this particular instance, the parents of young penguin chicks were more reluctant to come to the beach where their chicks were, because of the threat posed by the human visitors. Thus, many of the penguin chicks were not getting enough food. This is a great example of why it’s important to consider all aspects of penguin behavior before deciding if humans should interact with these animals. Here are a few ways people are able to view penguins in the wild in a safe manner for both the people, and the penguins:

Gentoo Penguin with its chicks in the wild
Cruise ship passengers looking at penguins
Cruise ship passengers looking at penguins in Antarctica

Cruise Expeditions to Antarctica

These ecotourism trips through numerous cruise operators provide excellent adventures for people willing to pay for them. Expert researchers and travelers lead tourists to the very ends of the Earth in search of incredible wildlife encounters. People planning on taking these trips can feel secure that they will always maintain a respectful distance from all penguins and other wildlife they might see. In addition, most tour operators in Antarctica have pledged to act responsibly with the wildlife and the environment. Be sure to check that your tour operator is a member of IAATO, the International Association of Antarctic Tour Operators, which is the “organization founded to advocate and promote the practice of safe and environmentally responsible private-sector travel to the Antarctic.” If your selected tour operator is not a member or IAATO, they likely have not officially pledged to protect the Antarctic environment during their tour activities.

Patagonia and Australia have great places to see penguins in the wild

Tierra del Fuego, Argentina

A local tour company takes visitors by car and boat to Martillo, an island home to Magellanic and Gentoo penguins. This is a great tour for people that want a relaxed, casual penguin viewing experience, plus there’s the added benefit of the tour guides ensuring that you stay a safe distance from the penguins.

Phillip Island, Australia

This island is home to a large population of Little Penguins. Visitors can stand on elevated platforms at a secure distance from the birds in the evening and watch the penguins return to their roosting grounds. This is one economical option that penguin lovers can take advantage of without breaking the bank. Phillip Island Nature Park offers these excellent encounters with Little Penguins, and as a conservation-based not-for-profit, the penguin-viewing fees go straight back to research and conservation of the birds that live there.

Viewing penguins in captivity

Many zoos and aquariums around the world host excellent penguin exhibits that allow visitors to get far closer to the birds than they would be able to in the wild. Visiting a zoo or aquarium is a great choice if you want to get close to the birds, learn interesting animal facts, and make a difference for conservation. Many zoos and aquariums are accredited by the AZA (Association of Zoos and Aquariums). AZA is an international group of animal care professionals that sets strict standards of excellence for zoos and aquariums around the world. Many zoos and aquariums that are AZA accredited also host Species Protection Plans (SSPs). SSPs are projects run by zoo or aquarium professionals that aide in the conservation of an animal species that is in danger of extinction. Many of these SSPs breed animals, like penguins, in captivity that can eventually be reintroduced in the wild. Zoos and aquariums also often provide great homes for animals that were injured or orphaned in the wild and would be unable to survive on their own.

Penguins at a local zoo
Penguins at a local zoo    Photo source: Elfix,  GNU Free Documentation License

Ultimately, the decision of how and where you view penguins is up to you. Hopefully this guide helps provide a greater understanding of how penguins can be viewed in safe, sustainable ways. Ecotourism and citizen-science activities (such as birding) are great ways for people to come close to nature and provide funds or data to researchers that are trying to save wildlife species. Your decision to safely encounter penguins in the wild can make a big difference in conservation, helping to keep penguins waddling for generations to come.

Have you seen penguins in person? If so, where? If not, where do you plan to go or where would you like to go? We love hearing from you.

 

Want to read more about penguins? Read some of our other blogs:

Penguins Wrapped in Plastic

Penguins Wrapped in Plastic

by Nataly H. Aranzamendi

Every day we encounter more and more animals affected by our plastic consumption and penguins are not the exception. Can we do something to stop it?

How much plastic do these penguins face?

An overview of the problem

Plastic found in our oceans comes mostly from land based sources (80%), with only 20% from marine sources. Half of the latter are mostly abandoned fishing gear: fishing nets, lines and parts from abandoned vessels (10% of total plastic)¹.

Plastic from land sources reaches the ocean mainly through rivers and, in fact, the 20 most polluting rivers are in Asia. However, not all rubbish is exclusively produced in Asia. This is because high income countries sell non-recycled plastic to low income countries, which usually have poor managing systems¹. Thus, it is likely that the plastic entering the ocean from rivers comes from everywhere in the world.

Since plastic can float, driven by oceanic currents and the wind, islands of floating plastic are concentrated in some latitudes with more frequency than in others. So, although less people live in coastal areas in the southern hemisphere, there is a lot of plastic concentrated in the southern oceans¹, putting penguins at a high risk of contact with plastic.

Examples of the plastic trash and debris we have collected during our conservation and habitat rehabilitation projects.

How does plastic in the ocean affect penguins?

Why exactly is plastic bad for penguins?

Penguins can interact with plastic in three ways: by entanglement, by directly eating it or by indirect ingestion of other organisms that have consumed microplastics2. Microplastics are produced from the breakdown of bigger pieces of plastic, which end up ingested by small organisms and transferred along food chains2.

Tangled in a web of plastic: Approximately 36% of seabird species have been found entangled in plastic litter. Most of the time, fishing gear incorrectly disposed of can be blamed, accounting for 83% of bird entanglements (although it is hard to differentiate the losses due to bycatch)3.

Unhealthy food: Fortunately, penguins seem to be eating less plastic than other seabirds of their same size, but they are still doing it4. Penguins could mistake floating plastic as their favorite food items. Plastic bags might look like jellyfish and floating plastics like fish.

Moreover, plastic floating over months in the ocean releases a volatile compound (DMS) that smells like food, confusing the olfactory senses of birds5, although presently there is limited knowledge of how much this is true for every species6. In any case, several species of penguins that have been found beach-washed, contained significant amounts of plastic in their intestinal tract7. Whether this ingestion caused the stranding events is still unknown.

The invisible food: Microplastics can contain chemicals and contaminants that interfere with biological processes in animals2. The exact mechanisms that affect animals are still debated, but the presence of microplastics is ubiquitous worldwide in aquatic environments.

What can we do to stop this threat of plastic to penguins?

What can we do to help?

Heartbreaking photos of our loved seabirds eating plastic leave us wondering if there is anything that we can do. The answer is yes! We can chose to not let plastic win and take individual actions to help our birds.

Beware of what kind of fish you buy and find out how it was caught. Some fish are caught with more sustainable practices than others. Avoid eating fish that were caught with dubious high-impact practices to send a message (i.e. we do not buy bycatch!). Follow the actions of your local government regarding fishing practices and express your opinion. This will help fish and penguins!

Do not rely on recycling. Remember that many countries are doing their best to recycle as much as they can, but these efforts are still far away from efficiency, and most countries are doing it poorly.

Avoid single use plastic. Analyze every item that goes in your shopping bag and items of your daily routine. Do we really need a daily disposable coffee container? Do we need tomatoes wrapped in plastic?

Look for alternative options e.g. buy loose tea instead of individually packed tea bags, replace your old shampoo bottle for a shampoo bar, let ear buds be a thing of the past, etc. See some of the great ideas in this blog: Go Green: Eco-Friendly Products We Should All Be Using

It might feel like one person will not make a difference, but millions of people changing their habits for sure will be noticed. Remember that we can make a difference in the future of our seabirds and our beloved penguins.

Thoughts about the unfortunate results of plastic/litter? Any steps that you will take? Love hearing your thoughts.

Also, read more about penguins in our other blogs:

1. Ritchie H. & Roser M. (2018) – “Plastic Pollution”. Published online at OurWorldInData.org. Retrieved from: ‘https://ourworldindata.org/plastic-pollution’ [Online Resource]
2. Avio, C. G., Gorbi, S., & Regoli, F. (2017). Plastics and microplastics in the oceans: From emerging pollutants to emerged threat. Marine environmental research, 128, 2-11.
3. Ryan, P. G. (2018). Entanglement of birds in plastics and other synthetic materials. Marine pollution bulletin, 135, 159-164.
4. Wilcox, C., Van Sebille, E., & Hardesty, B. D. (2015). Threat of plastic pollution to seabirds is global, pervasive, and increasing. Proceedings of the National Academy of Sciences, 112(38), 11899-11904.
5. Savoca, M. S., Wohlfeil, M. E., Ebeler, S. E., & Nevitt, G. A. (2016). Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds. Science advances, 2(11), e1600395.
6. Dell’Ariccia, G., Phillips, R. A., Van Franeker, J. A., Gaidet, N., Catry, P., Granadeiro, J. P., … & Bonadonna, F. (2017). Comment on “Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds” by Savoca et al. Science advances, 3(6), e1700526.
7. Pinto, M. B., Siciliano, S., & Di Beneditto, A. P. M. (2007). Stomach contents of the Magellanic penguin Spheniscus magellanicus from the northern distribution limit on the Atlantic coast of Brazil. Marine Ornithology, 35, 77-78.

Penguins of the past, what do we know about them?

relative large size of the Anthropornis penguin

Penguins of the Past – Prehistoric Penguins

by Nataly H. Aranzamendi

Millions of years ago, the world was a very different place from what we see now. Colossal giants wandered through planet Earth and many of them were quite different from the animals that remain today. However a group of flightless birds was already represented: the prehistoric penguins.

When did prehistoric penguins first appear?

George G. Simpson¹, an important paleontologist and geologist, classified ancient penguins in three groups: Palaeeudyptinae, Paraptenodytinae, and Palaeospheniscinae‎. He originally recognized about a dozen species, but since then there are new additions to the family tree of penguins nearly every year.

Based on previous DNA and fossil evidence, the possible dates for the earliest ancestor of penguins were originally calculated to date back 40 million years ago. However, recent evidence² has expanded those dates backwards and changed what we know about the presence of penguins. The oldest penguins might just date back to 60 million years ago during the early Cenozoic or late Cretaceous periods. This is 20 million years older than previously thought — and when dinosaurs were wandering the Earth!

relative large size of the Anthropornis penguin
Photo Credit: By Discott – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=59535142

Did prehistoric penguins look like penguins of today?

The ancestors of penguins were slightly different from extant species. The oldest penguins probably had already lost their typical bird plumage, but their semi-rigid flipper — which helps them to swim in the ocean and gives them their hydrodynamic shape — was not totally transformed in all species.

An agreement among scientists seems to be the fact that there were some prehistoric penguins that reached big sizes. This was inferred from fossil records and particularly recorded for the oldest groups. For example, the largest fossil penguin was Anthropornis nordenskjoeldi, a penguin that could have reached almost two meters tall. This species lived around 33-45 million years ago. Another fossil found recently in New Zealand² was likely of a similar size as Anthropornis. Thus, big penguins were not uncommon. Nonetheless, a decline in body size occurred for the later groups³.

Two species of the genera Kairuku4 that lived in New Zealand in the late Oligocene (23-34 million years ago) depict some morphological differences between them and extant (currently living) species. Those penguins already showed the typical upright penguin posture, as well as long flippers and short, thick legs and feet. However, their bodies were much more slender than penguins of today and their bills much longer.

Prehistoric penguins lived in the same places as penguins of today

Prehistoric penguins shared the same distribution as their current relatives. They were found in the Southern Hemisphere including Antarctica. Fossil records of extinct penguins have been found in Antarctica, New Zealand, Australia, Argentina, Chile, Peru and South Africa.

Places where fossils were found show a relatively high penguin diversity, which possibly peaked at the late Eocene and early Oligocene. A high penguin diversity was probably related to the expansion of cold waters and the change in favorable conditions for diversification5 that followed the separation of continents from Antarctica.

In the late Paleocene, Antarctica and the surrounding continents were in very different geographic positions from where they are located today. Australia and South America were closer to Antarctica but increasingly shifted northwards and separated more and more from the frozen continent. Such events probably had a big influence in the biogeography of penguins. Isolation from the old continent and new climatic conditions most likely provided optimal conditions that made diversification of species possible.

Photo credit: JJ Harrison

However, continental species did not remain completely isolated, since DNA evidence has shown us that multiple independent dispersal events could have occurred. In Australia, for example, new species of penguins arrived to the continent at different historical times³. Besides the fact that Australia hosted several species of penguins, currently there is only one species left there, the Little penguin.

Based on the later example and extensive fossil record, it seems that penguin diversity was high everywhere but declined during more recent periods. Why penguin diversity plummeted is still a mystery although several factors could have contributed. Perhaps the appearance of potential competitors like cetaceans (dolphins, porpoises and whales) and pinnipeds (seals and sea lions) displaced them and/or deprived them of food. Another hypothesis is that environmental conditions continued changing and food became scarcer.

In any case, the constant exploration and finding of new fossils will probably keep increasing our knowledge of the penguin family tree. Similarly, the advancement of technology and improvement of data based on DNA analyses will keep providing information of the exact time when prehistoric gigantic penguins were wandering our planet.

Did you know all this about the history of penguins? Did you learn something new by reading this? Let us know what you think!

 

Also, read more about penguins in our other blogs:

References:

1 Simpson, G.G. 1946. Fossil penguins. Bulletin of the American Museum of Natural History, 87 (1): 1-100, figs. 1-33. New York.

2 Mayr, G., De Pietri, V. L., & Scofield, R. P. (2017). A new fossil from the mid-Paleocene of New Zealand reveals an unexpected diversity of world’s oldest penguins. The Science of Nature, 104(3-4), 9.

3 Park T, Fitzgerald EMG, Gallagher SJ, Tomkins E, Allan T (2016) New Miocene Fossils and the History of Penguins in Australia. PLOS ONE 11(4): e0153915

4 Ksepka, D.T., Fordyce, R.E., Ando, T. and Jones, C.M. (2012). «New fossil penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand reveal the skeletal plan of stem penguins». Journal of Vertebrate Paleontology 32 (2): 235-254

5 Acosta Hospitaleche, C. I. A., Griffin, M., Asensio, M., Cione, A. L., & Tambussi, C. P. (2013). Middle Cenozoic penguin remains from the Patagonian Cordillera. Andean Geology vol.40 no.3 set. 2013

Internal GPS – The Science Behind Penguin Navigation

Penguins Have Internal GPS Systems

By Mike King

Nature constantly presents organisms with new challenges along their way to surviving to reproductive age and leaving behind offspring. Animals meet these challenges by adapting incredible traits that allow them to thrive in their environment. When reminded of these adaptations, one might think of Bat-eared Foxes that use their massive ears to hear prey underground for great distances, New Caledonian Crows that sharpen sticks into hunting hooks, or Orchid Mantises that perfectly imitate flowers to ambush pollinating insects. Less commonly do we consider adaptations under the surface layer of animals. Are there mechanisms within an organism’s body as astonishing as those we can observe with the naked eye? As it turns out, penguins have a few tricks up their sleeves that may surprise you.

Penguins swimming in the ocean
Penguins swimming in the ocean

Penguins swim for hundreds and even thousands of kilometers in the ocean, and can find their way home

Penguins are extremely active animals. From lengthy Emperor Penguin migrations to complex diving patterns exhibited by krill-hunting Gentoos, movement is of critical importance to every penguin species in the world. Many species spend all day out on the water swimming and hunting for food. With all of this waddling around, how do they find their way back to the colony? As it turns out, all birds possess some extraordinary adaptations for navigation; although penguins have the added disadvantage of being flightless. This makes it impossible for them to soar above the horizon in search of familiar landmarks leading them home. Scientists are beginning to understand some of the ways penguins can locate their colonies after long days spent far away.

Penguin researcher Anna P. Nesterova and her team recently spent time studying King Penguin navigation in Antarctica. They observed that King Penguins live in massive colonies that seem to be quite difficult to navigate. How then, do penguin parents find their way back to their chicks after a day out searching for food? It is known that penguins can recognize individuals through vocalizations, but this is only an effective strategy for King Penguins within eight meters of their chicks.

Image Source:
apnesterova.wixsite.com/anna-p-nesterova

Penguins can also find their chicks in a colony of thousands of other penguins

Some penguins in the study were documented taking very lengthy, indirect paths to their chicks when returning to the colony after feeding to avoid aggressive encounters with resting neighbors. So, do King Penguins simply wander, or is there something more to their navigation? The answer may have something to do with nighttime movement. As it turns out, many penguins were observed to leave and return to the colony in the middle of the darkness of night. Although King Penguins can see 1.5 times better than humans, they are still incapable of seeing landmarks well at low-light levels. The researchers involved in this study believe that over time, penguins can learn the acoustic landscape of their colony, thus navigating by the unique sounds of their neighbor’s voices. It is also possible that King Penguins use a method that science had only speculated about until this year—magnetism.

Image Source:
Overexpression in Yeast, Photocycle, and in Vitro Structural Change of an Avian Putative Magnetoreceptor Cryptochrome4, pubs.acs.org/doi/abs/10.1021/bi501441u?journalCode=bichaw

For years, researchers have known that birds navigate by sensing the magnetic field of the earth; but until just recently we did not know how this was accomplished. It was observed that birds have high levels of iron within their bills, which could possibly be used as a sort of compass. This was the prevailing viewpoint in the scientific community for years, but it lacked credible evidence. It seemed for a long time that the mystery of bird navigation would remain unknown to man—until now. Just this year researchers analyzed a special protein found within the eyes of birds, and it turns out it is critically important for navigation. This protein, called Cry4, is a type of photoreceptor that detects blue light. Birds are able to use these photoreceptors to actually see the magnetic field of the Earth. This amazing discovery helps us to understand how migratory birds can fly with perfect orientation through the complete cover of darkness. This protein has not yet been analyzed within the eyes of penguins, but Cry4 may be an essential tool for these seabirds to find their way to their chicks.

There are so many possibilities — how do penguins really find their way?

Unfortunately, we do not yet know whether King Penguins use acoustic landscapes, magnetic fields, or their memory to navigate through crowded colonies. However, each of these adaptations can and should be appreciated for the ingenious ways they help an organism rise above the challenges presented by its environment. People often use the term “life will find a way” to describe situations in nature that seem too extreme to support living organisms, yet still do. Through the observation of evolutionary adaptations such as navigation, we are better able to understand the extraordinary nature of life to overcome seemingly impossible odds. This characteristic defines the very concept of life—to continue changing, adapting, and evolving alongside the surrounding world; constantly pursuing a level of ecological balance that allows an organism to flourish despite overwhelming challenges presented to them.

What do you think about how penguins get around? Did you learn something new? Would love to hear what you think, what you learned, and more!

 

Visit our other recent blogs to read more about penguins:

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