Bright Goes North

Guest post by Kate Davies, a recent MEnvSc Graduate from the University of Toronto-Scarborough

She could feel the pull in her body. It was time.

She had done this journey before, but even the first time it felt familiar. Like a memory that she was born with.

She was called Bright because she was known by the others for her deeply golden tail feathers and her clear eyes. Bright was late leaving her winter home this year, and many of the others had left already, departing at the first signs of change. The air had started to feel heavy signaling that the rains would come soon. She had to start north before daybreak. Bright hopped around the tree canopy from branch to branch. She dropped her wings by her sides and fanned her tail to spook the insects and quickly grab them in her beak. She had spent her winter in brushy scrubland that was not the best feeding grounds, but she was older now and had less energy to defend her place in the boggy wetlands filled with ripe insects. She ate her fill before she spread her wings and started to carry her small light body out over the immense open waters. Crossing the gulf was frightening the first time, but she knew even on her first trip that the sky would end, and she would see green again. She traveled in a loose flock with some other Redstart females, some yearlings and others Bright knew from previous flights. She hoped some of her daughters were here, now grown she would not have known their calls. The males always left first; they would meet them in the northern home.

Illustration by Kate Davies

The journey across the gulf lasted into the night, the winds were not favourable this year. Bright and the others she travelled with were weak and needed to eat. There was a wetland they had visited as a stop every year, but Bright was worried they had taken a wrong turn. This was the right place but there was not water, few plants, and it had been filled with stone, humans and a glowing hum. It seemed as she flew north every year there were more angular stone forests filled with humans. Some could tolerate these stone forests but Bright and her companions preferred trees and grass. The birds who lived there like pigeons and house sparrows spoke a different language than the other birds she knew, and some said they came across the water bigger than the gulf. So, despite their exhaustion the females kept flying until they could find somewhere to eat and sleep. They had to settle for an area where the plants all grew in rows, a farm, but there was a river and some insects so it would do for today. These human places had different dangers and predators than in the forests and fields. Bright knew to be cautious of owls, hawks and snakes but where there were humans, other dangers were lurking. They were too tired to find anywhere else to sleep. Bright noticed that her party had shrunk by a few - some were so tired they may have rested in the stone forest. Bright hoped the others would be alright and would catch up to the group.

They travelled for a few more days, finding quiet places to rest. They avoided the stone forests as much as they could with their bright lights, constant noises and hums. They rested at another farm on the fifth night. Bright and her companions were huddled in a dense thicket of bushes near a field and river. They had fallen sound asleep for the night. In the nearby tall grasses, a pair of green eyes shone in the moonlight. A barn cat had been stalking the birds, she moved quietly, softer than the wind. The cat slinked under the low branches of the bush without a sound and spotted a bird on a low branch she could easily reach.  Bright opened her eyes to see one of the yearlings was in the cat’s fangs - she was lost. Bright and her companions moved to another row of bushes closer to the stream, they were all shaken and tired. Fear and anxiety overtook the small flock, they didn’t sleep anymore that night. Bright was relieved when the sun crept over the horizon and they could continue northward.

Illustration by Kate Davies

The air was warm, and they had been lucky that there were no storms along the way. They started to see some males that day, and a few of her companions ended their journey to find a mate. Bright continued her northward flight as did most of the females until they made it over the big lake. It was not as big as the gulf, but it could be dangerous, as there were many humans and stone forests around the water. There were predators near every shore, some had been here all winter and were eager for the small songbirds to return so they could fill their bellies.

Since Bright had left late this year, she was eager to build a nest and find a mate. She decided to end her journey on an island at the north shore of one of the long lakes. Most of the others continued north. She was near a stone forest but on an island that was far enough away that the sound of the waves drowned out the hum and noise. It was the time of year where the air was filled with song from many different birds. She fluttered around the island listening for males of her kind, trying to find one who sang strong and clear. She followed a song to a male high up in a red maple tree. In her mind she identified him as Flicker - he was very expressive in the way he flicked his tail. He took her to the sites he had scouted for nesting to see if she approved of any. She was happy that she would be his first and maybe only mate, which would afford her more protection. She picked the third site he showed her. It was a dense area of red dogwood that was covered in fresh young leaves. They were close to a pond in an area rich with insects. She started to gather twigs and build her nest there while Flicker stayed close singing to warn others away from his mate and territory. Together they had four eggs and Bright was happy with her clutch size; it was more than last spring. She left the nest to find some food in early morning and Flicker guarded the eggs. She was chasing a particularly acrobatic fly though the bushes when suddenly a great force stopped her flight and she fell to the ground. She could feel and taste the warmth of blood in her mouth, her beak was fractured, her head pounded, and she could not catch her breath. She had only seen branches before her, it was like a reflective pond in the air made of stone. Bright wanted to live, she wanted to get up go back to Flicker and the young. She could not move; she let out her last breath and died.

The new gardener came around back of the building to trim the forsythia that was long overgrown. At the base of the bush under the window lay a female American Restart, she was dead. The garden gasped and cried out ‘Oh no!’ Another window strike, this was the sixth one this month and perhaps it would encourage management to finally birdproof the windows, thought the gardener. She buried the bird in the garden with a tear for its loss of life and trimmed the forsythia. On her break she reported the window strike on the Fatal Light Awareness Project (Flap) website and continued her duties.

Flicker realized that Bright would not return - what had become of her? He could not care for the babies alone. He would have to leave them. He sung a mournful song for Bright and flew off in search of a new mate hoping that it wasn’t too late.

 

 

Further Reading and References

Further reading: Online resources

The Cornell Lab - All about birds – American Redstart

Overview: https://www.allaboutbirds.org/guide/American_Redstart/overview and

Species account: https://birdsna.org/Species-Account/bna/species/amered/introduction

Toronto and Region Conservation Authority. The American Redstart: A Bird On the Rise In the GTA https://trca.ca/news/the-american-redstart-a-bird-on-the-rise-in-the-gta/

Boreal Songbird initiative. A guide to boreal birds https://www.borealbirds.org/bird/american-redstart

Ontario Nature. Migratory Birds https://ontarionature.org/campaigns/migratory-birds/

North American Birds Declining as Threats Mount By Mel White for National Geographic https://www.nationalgeographic.com/news/2013/6/130621-threats-against-birds-cats-wind-turbines-climate-change-habitat-loss-science-united-states/

Birdwatchers Digest. Your Bird Questions Answered: Flight and Migration https://www.birdwatchersdigest.com/bwdsite/connect/youngbirders/your-bird-questions-answered-flight-migration.php

 

 Further reading: peer reviewed literature

Cohen, E. B., Rushing, C. R., Moore, F. R., & Hallworth, M. T. (2019). The strength of migratory connectivity for birds en route to breeding through the Gulf of Mexico. Ecography, 42(4), 658–669. https://doi.org/10.1111/ecog.03974

Cooper, N. W., Sherry, T. W., & Marra, P. P. (2015). Experimental reduction of winter food decreases body condition and delays migration in a long-distance migratory bird. Ecology, 96(7), 1933.

Hill, G. E. (2004). A Head Start for Some Redstarts. Science, 306(5705), 2201–2202.

Germain, R. R., Marra, P. P., Kyser, T. K., & Ratcliffe, L. M. (2010). Adult-Like Plumage Coloration Predicts Winter Territory Quality and Timing of Arrival on the Breeding Grounds of Yearling Male American Redstarts. The Condor, 112(4), 676–682. https://doi.org/10.1525/cond.2010.090193

Norris, D. R., Marra, P. P., Bowen, G. J., & Ratcliffe, L. M. (2006). Migratory connectivity of a widely distributed songbird, the American Redstart (Setophaga ruticilla). The Auk, 123(4), 14.

Norris, D. R., & Marra, P. P. (2007). Seasonal Interactions, Habitat Quality, and Population Dynamics in Migratory Birds. The Condor, 109(3), 535–547.

Marra, P. P., & Holmes, R. T. (2001). Consequences of Dominance-Mediated habitat segregation in American Redstarts during the nonbreeding season. The Auk, 118(1), 92–104.

McKinnon, E. A., Stanley, C. Q., & Stutchbury, B. J. M. (2015). Carry-Over Effects of Nonbreeding Habitat on Start-to-Finish Spring Migration Performance of a Songbird. PloS One, 10(11), e0141580.

Morris, S. R., & Glasgow, J. L. (2001). Comparison of spring and fall migration of American Redstarts on Appledore Island, Maine. The Wilson Bulletin, 113(2), 202.

Smith, R. J., Mabey, S. E., & Moore, F. R. (2009). Spring Passage and Arrival Patterns of American Redstarts in Michigan’s Eastern Upper Peninsula. The Wilson Journal of Ornithology, 121(2), 290–297. https://doi.org/10.1676/08-051.1

Wuethrich, B. (1998). Songbirds Stressed in Winter Grounds. Science, 282(5395), 1791–1794.

 

 

A bird in the hand… Worth a bunch in the bush?

Guest post by University of Toronto-Scarborough Masters of Environmental Science Student Amica Ferras

     In less than a week, Christopher Filardi achieved a level of cyber-fame worthy of this digital age— but for all the wrong reasons. If you haven’t heard of him yet, that’s okay. Not all of us peruse biodiversity articles over our morning cereal. Here’s what you’ll need to know to hold your own around the water cooler.

Photo: University of Kansas

Christopher Filardi is the director of Pacific Programs at the American Museum of Natural History’s Center for Biodiversity and Conservation. This past September he and his team were part of an international expedition to the mountains of Guadalcanal, one of the islands in the Solomon Archipelago. Lead by native islanders, the team was on a mission to assess the biodiversity and habitat constraints of this unique region in order to develop a tailored conservation strategy. It was there on those mysterious island mountains that Filardi happened upon a true legend by any biology geek’s standards — the Guadalcanal Moustached Kingfisher. Even if you have zero interest in species biology, the stats on this bird are impressive. Only three sightings of the Kingfisher have been documented in all of history: a single female captured in the 1920’s, and another two in the 1950’s. No male specimen had ever been recorded and no live animal had ever been photographed. This bird can play a mean game of Hide-and-Go-Seek.

Upon discovery of the Kingfisher colony, Filardi and his team set to work. Calls were recorded, habitat was meticulously documented, behavior and motion patterns were scrutinized and population dynamics were assessed. And then, they killed one. (Cue the angry villagers with pitchforks and hippies with signs).

The collection was purely scientific. Filardi and his team stuck to a field biology motto of collect, dissect, but ultimately respect. Filardi hoped that the Kingfisher specimen would open the door to discovering more about the elusive species and their ultra-specific habitat. But the road to media-hell is paved with good intentions, and as the story spread like wildfire Filardi’s actions fell under attack. His ‘collection’ was deemed “perverse, cruel” by a representative from PETA to the Daily News, and the UK online Daily Mail described it as “slaughter”. The story exploded, appearing in the Huffington Post, Washington Post, Nature World News and Audubon, just to name a few. For those links and more I suggest checking the wonderful world of Google, but I will personally recommend that you read Fildari’s self-defense in Audubon https://www.audubon.org/news/why-i-collected-moustached-kingfisher, and the Toronto Star’s coverage of the controversy http://www.thestar.com/news/insight/2015/10/17/why-a-scientist-killed-a-bird-that-hadnt-been-seen-in-50-years.html. The Star does a fabulous job of presenting both sides of the story, and also goes into detail about the rather dubious past of field biology.

In the 1700’s and 1800’s specimen collection was more sport than science. It was a my-stuffed-animal-carcass-is-bigger-than-your-stuffed-carcass race, and rare species paid the ultimate price. Great Auks, for example, upon classification as endangered in 1775, were hunted at an alarming rate by naturalists attracted to its rareness. In 1884 a final pair of Auks was caught by fishermen, and no Auk has ever been sighted since. Specimen collection has come a long way since then though, and field biology has contributed to some groundbreaking scientific discoveries. Consider eggs— comparisons of eggshell thickness from samples collected across decades was used to identify the detrimental effects of DDT and other pesticides to natural ecosystems.

So, those are the facts. And my opinion about it? I’m siding with Filardi. Science has come a long way from naturalist trophy hunting in the 1800’s. Nowadays, before even setting foot outside of the lab scientists must undergo a rigorous evaluation process to determine if collection permits will be granted. Cost-benefit analyses, potential outcomes, and fragility of a species and ecosystem are all heavily weighted in before a decision is reached. Filardi’s expedition was no exception to this rule. (And for anyone questioning the usefulness of collections at all, I suggest you read the following article http://biology.unm.edu/Witt/pub_files/Science-2014-Rocha-814-5.pdf. I’d be happy to argue with you on that front another day).

It wasn’t as if Filardi saw the Kingfisher, pulled a net out of his pack and started swinging. After discovering the Kingfisher colony, the bird was carefully observed over several days. Input from the native islanders, assessments of habitat resilience and population robustness were all carefully analyzed before deciding to humanely collect the single male specimen. The unwilling sacrifice of the Kingfisher was honorably recognized, and the collection will be worthwhile if Filardi has anything to do with it. Scientists now have access to a complete set of genetic information for the Kingfisher. It will now be possible to undertake full molecular, toxicological and evolutionary diagnostics. Scientists may discover disease and pollutant susceptibilities that will guide Kingfisher protection efforts, or identify a direct evolutionary pressure to explain the appearance or behavior of the birds. At a more macro level, the specimen could reveal a shared trait between all high-elevation avian species or allow for an assessment of the particular environmental pressures the island ecosystem exerts over its inhabitants.  

Remember though, the point of the Guadalcanal expedition was not a Kingfisher hunt, but an internationally commissioned excursion to study the biodiversity and ecosystem threats in the Solomon Archipelago. Working with native islanders and Solomon government officials, Filardi’s team was working to establish a conservation strategy to protect the unique island system. The Pacific Island tribes have tended to their mountainous lands for decades, but recent international development has threatened the natural state of the ecosystem. Intensive mining and logging ventures have already begun transforming the lowlands of the islands, and climate change at large is effecting the delicate balance of ocean and forest features that unique species like the Kingfisher rely on. For species limited to a single isolated habitat, even minor changes in soil pH, precipitation or fluid motility can have astronomical effects on species survival. These are not the resilient squirrels and raccoons we in North America watch thrive everywhere from lush forests to derelict urban alleyways. Filardi’s collection will go a long way in identifying what needs to be done to protect these habitat-specific island species.

In fact, it already has. Discovery of the Kingfisher led Filardi to talks with local tribes and the Solomon government which culminated in formal agreements to protect the island mountain region under the recently passed Protected Areas Act. Filardi has already booked a return flight to Guadalcanal to help negotiate the next steps in this exciting conservation effort.

So, what do you think? 

Where is south? Uncovering bird migration routes

Guest post by John Viengkone, currently enrolled in the Professional Masters of Environmental Science program at the University of Toronto-Scarborough

Wilson’s Warbler http://www.utahbirds.org/birdsofutah/BirdsS-Z/WilsonsWarbler.htm

There are approximately 450 native migrating bird species that for at least part of the year reside in Canada, but where do they go when they aren’t in the True North Strong and Free? If you ask just about anyone, they’ll tell you that birds fly south for the winter, but where exactly is south? South could be as close as the next city, the USA or as far as Tierra Del Fuego. Also do they make stops on their way to this “south” and do they mix with other populations? The truth is there isn’t much information on where many migrating species go or the route they take to get there.

But why should we care where they go when they leave Canada, they seem to always come back in the spring. The truth is not all birds are coming back, there has been a marked decline in the population size of many migrating neotropical bird species. As the leading cause of species loss, humans need to figure out whether these bird populations are facing stressors in their breeding, wintering, stopover range or some combination of the three so we can help manage them. The first step in doing this is learning the birds’ migration route. 

The effort to understand the movement patterns of birds began in North America during the 1800s when the famous ornithologist John James Audubon started tying silver string to the legs of eastern phoebes, Sayornis phoebe, to see if individuals that left in the fall returned in the spring. Of all the birds Audubon marked, 2 returned in the spring. This little experiment transformed into the bird banding/ringing program we know today with different coloured metal bands replacing the pieces of silver string.

Though the bird banding program has been essential to the understanding of bird ecology, life history and migration it is has one major flaw. This flaw is that banded birds must be spotted again and it’s estimated that only 1 in 10,000 banded birds are recaptured, leaving a large data gap. So why use bands, why not use GPS tracking devices? Well, they do for larger birds but for many bird species the size and weight of a tracker is too much of stress so a better solution is needed. This solution is up and coming from Dr. Kristen Ruegg’s lab at UCLA and it has been dubbed The Bird Genoscape Project.

Ruegg and company have taken on the task of creating a protocol that will allow them to identify where a migrating bird has come from by using just a feather. To get a full comprehensive understanding of this protocol please refer to Ruegg et al. 2014 but I’ll briefly explain their methods here: Variation in DNA is what makes individuals unique but a huge portion of an organism is actually shared with the individuals of the same species. As groups or populations of a species become more isolated and breed with other individuals in their populations more, the populations start to diverge, this is population differentiation. Individuals in a breeding population will be more similar to each other than to other populations.

The UCLA team used the concept of population differentiation to find the small bits of DNA, called single nucleotide polymorphisms (SNPs), that are unique to each breeding population, a genetic fingerprint some might say. For their study they looked at the Wilson’s warbler, Cardellina pusilla, taking small blood samples from individuals in each breeding population and each population’s genetic fingerprint was made.

With a genetic fingerprint for each breeding population Dr. Ruegg and her collaborators were able to collect feathers from Wilson’s warblers across North America and identify where it came from with an 80-100% success rate. So a feather collected in Colorado in the late fall could be traced back to the British Columbia breeding population, meaning Colorado is a stop off point. This solves the major problem that banding had; you don’t need to come in contact with the same bird to get information, any bird in the species will work. 

From Ruegg et al. 2014. Each colour depicts a breeding population, arrows are stopovers and circles are wintering grounds

An interesting finding from UCLA’s study was that there are 6 breeding populations of Wilson’s warblers opposed to the 2-3 that biologist previously thought and that 3 of the breeding populations actually share a wintering ground and flight path. Two of these three breeding populations are stable but one population is declining, suggesting the cause of decline stems from the declining population’s breeding ground. If the issue stemmed from the wintering ground of the flight path, the other populations should be affected too.

So what’s next? Ecological managers now know where the issue is likely originating from for the Wilson’s warbler but still need to identify the root cause. As for The Bird Genoscape Project, Dr. Ruegg has moved on to repeating this study with the American Kestrel. There is also work being done with museum samples to see if ranges and flight paths have shifted with time. It’s looking like The Bird Genoscape Project can only get bigger, spreading to more migrating bird species and become an essential tool for bird conservation just as bird banding did in the past.

For more information see:

Ruegg K.C., Anderson E.C., Paxton K.L., Apkenas V., Lao S., Siegel R.B., Desante D.F., Moore F., and Smith T.B. 2014. Mapping migration in a songbird using high-resolution genetic markers. Molecular Ecology 23:5726-5739.

Kristen’s interview with Podcast Eye’s on Conservation is available on iTunes

Can you teach an old bird new (migratory) tricks?

Jennifer A. Gill, José A. Alves, William J. Sutherland, Graham F. Appleton, Peter M. Potts and Tómas G. Gunnarsson. 2013. “Why is timing of bird migration advancing when individuals are not?” Proc. B. Vol. 281, no. 1774.

Phenological responses have been used as one of the major indicators of climate change. The timing of flowering and fruiting, the return of migrant birds and insects from winter habitats are easily and often measured, and records going back decades or centuries sometimes exist. Most importantly, shifts in phenological indicators are some of the strongest connections between rising temperatures and biological and ecological responses (for example). There is plenty of evidence, for example, that some migrant bird species are returning to their breeding grounds earlier than ever. These migratory birds may be responding (via migration timing) to warming temperatures in several ways: there may be plasticity or flexibility in individual timing of migration which allows them to respond to changing temperature cues; or species may also show adaptation via changes in the frequency of individuals with different migratory timings (microevolution). In cases where migratory species are responding to climate change, distinguishing the mechanisms allowing them to do so is surprisingly hard. Early arrival of migratory bird species is often explained as being due to individual plasticity or flexibility in “choosing” the date of migration, but the majority of studies of this phenomenon include little or no information about individual behaviour, only changes in the mean date of arrival for the entire population.

For this reason, Gill et al. looked at individual, rather than average population, arrival dates for Icelandic black-tailed godwits in south Iceland. Icelandic black-tailed godwits (“godwits” for the sake of brevity) have shown significant advances in the last 20 years in the timing of their spring arrival to the shores of Iceland, and these advances appear to relate to increasing temperatures. The population has also been banded such that 1-2% can be individually identified and tracked throughout their migratory range. Although only adults (of unknown age) were banded at the start of the experiment in 1999, recently chicks have also been banded and released and so a wide range of demographic classes are included with the banded birds.

From Gill et al. 2013.

When Gill et al. looked at date of arrival across 14 years for each individual, their results were surprisingly clear and cohesive. As previously reported, the population mean date of arrival in South Iceland had advanced as much as 2 weeks. But, this advance is not reflected in individual timing of arrivals over that same period – if a bird tends to arrive on a given day, they will continue to arrive on approximately that day every year, independent of temperature conditions. Instead, the population trend appears to be driven entirely by birds born in recent years – young individuals (recently hatched) tend to have arrival dates much earlier than older individuals. At least for the godwits, population wide trends in migration dates are actually driven by only a subset of the individuals.

From Gill et al. (2013)

Often it is assumed that migratory birds are responding to warming temperatures on an individual level: individuals respond to changing cues, resulting in shifts in arrival date. This study suggests otherwise, and finds that the important mechanism is not individual plasticity or microevolution but rather related to demographic shifts in arrival time. As to why younger birds arrive earlier, it is not clear, but may relate to the observation that nest building and hatching dates are also advancing. It may be that natal conditions are important – the authors observed a variety of possibly inter-related changes such that hatching dates are advancing and chick sizes are increasing, and the suggestion that mortality rates of later arriving individuals may also be higher. "Environmentally induced advances in arrival dates of recruits could operate through: (i) carry-over effects of changing natal conditions, (ii) changing patterns of mortality of individuals with differing arrival times, or (iii) arrival times being initially determined by conditions in the year of recruitment and individuals repeating those timings thereafter."

These results make some predictions about which populations of migratory birds might have the most ability to respond to warming climate - most likely those with shorter migratory distances, shorter times to reproduction and shorter-lifespans (hence decreasing the lag-time required for the population to catch up to temperature). It may also have relevance for other non-bird species that also rely on careful timing between phenology and temperature. Correspondingly, it suggests limitations - if individual behaviour is so inflexible and constrained, our hopes that some species may respond to climate change with behavioural changes seem far to simplistic.

Measuring the Pacific extinction spasm

It is a fact that humans have caused numerous extinctions around the globe. Almost all of the large bodied mammals of North America disappeared after the arrival of humans sometime around 20,000 years ago –likely due to compounding effects of hunting and climate change.  This North American example has been controversial, largely because it constitutes a single observation. However, humans colonized the Pacific islands over a span of a couple of thousand years, between 3,500 to 700 years ago. Species extinctions followed these colonizations on each island, confirming the link between humans and extinctions. Yet how many species went extinct? This question may be relatively easily answered for large organisms since evidence of their existence is well recorded, but for small-bodied organisms like birds, this is a difficult question to answer.

In a recent paper in the Proceedings of the National Academy of Sciences, Richard Duncan, Alison Boyer and Tim Blackburn use sophisticated methods to estimate the true magnitude of bird (specifically nonpasserines –i.e., not perching or songbirds) extinctions on 41 Pacific islands (including islands from Hawaii, Melanesia, Micronesia and Polynesia). Estimating the number of extinctions prior to recorded history is an extremely difficult exercise, but Duncan and colleagues use a set of statistical methods (Bayesian mark-recapture) to produce reliable estimates. The data available include a spotty fossil record, and so the researchers needed an appropriate estimate of the number of species present on islands in the past. To do this they examined the fossil record and compared it to species that are found there today. Only a subset was found in the fossil record. From this, they determined how the number of fossils found, body size of the organisms and island size affected detection probability. With these informative detection probabilities, they were able to estimate past richness and compare that to today’s richness – and the difference is the number of extinctions.

Across these 41 islands, Duncan et al. estimate that human colonization resulted in at least 983 extinctions. Nine-hundred and eighty-three species are no longer with us because of the presence of humans. Coupled with human activities elsewhere, from over-hunting, habitat destruction and the introduction of non-native species, we responsible for thousands of extinctions. For the first time in Earth’s history, a single species (us) is the direct cause for thousands of other species going extinct. A paper such as this is an important analysis, but it certainly doesn’t make us feel good about ourselves.

Duncan, R., Boyer, A., & Blackburn, T. (2013). Magnitude and variation of prehistoric bird extinctions in the Pacific Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1216511110