Flying like a bird… might be harder than you think
Aves – Birds
Chip. Chip. Chip. Spring has come and the birds are singing! Every year, the sound of birds brings joy to people across the globe, a signal of the long-awaited change of seasons. For many, the return of birds is a cause for celebration – summer is almost here.
But hold on. Where are birds even returning from? Why did birds go in the first place? Do all birds leave? Now, if you’ve ever wondered what the answers are to any of these questions, you’re probably not alone.
Migration
Every year, without fail, BILLIONS of birds make a two-way trip with some flights over 10 thousand kilometres – known as migration. Birds are not the only animal known for this behaviour, but they do embark on some of the most fascinating journeys. Incredibly, snowy owls will travel across the continent going over 2800 km during their migration period. Or, according to this study, Albatrosses can even fly up to 15000 Km across the ocean in a single journey.
Because of this fantastic phenomenon, different birds are constantly passing through various regions of the world. One week you may see hundreds of Canadian geese frolicking along and by the next, they are completely gone without a trace- well, there will probably be some traces …
How do birds fly so far without getting lost?
If you asked me to wander thousands of kilometres without a GPS, I would lose myself in laughter. There’s no way anyone could find their way without any navigational skills or tools. Similarly, birds have multiple assets allowing them to navigate such magnificent journeys. However, they obviously don’t have access to an iPhone. Rather than referring to google maps and Wi-Fi connections, birds rely on the most ancient technologies. They refer to their acute senses and they tune in with the nature around them.
Like you and me, some species of birds will often look up at the starry night. Although, birds won’t be doing this for a sense of wonder. Instead, they use the alignment and orientation of the stars as a navigational asset showing them which way to fly.
Other types of birds have incredible eyesight and use their vision to help learn key landmarks along their journey, which they can remember year after year. For example, rivers, coasts, canyons, and mountains can all help birds keep their route consistent, allowing them to successfully find their destinations.
Masterfully, some birds are able to see and sense the earth’s magnetic field, always pointing them either north or south. While this sense is not fully understood yet, certain species have special chemicals in their eyes and brains that allow them to have their own internal compass orienting them in the right direction.
And of course, as with many members of the animal kingdom, birds may learn their journey from their parents. After embarking on the journey once or twice, the young bird will master their navigating skills and be able to go out on their own.
Why do birds migrate?
Now that we can understand just how birds navigate these journeys, it’s normal to wonder why they do it in the first place. The reason is simple – they do it to improve the chance of their, and their young’s, survival. The flying animal will cyclically change to areas of better habitat, weather, and food. If all the birds in the world remained still, there would be so much competition that survival would decrease drastically! We humans living in colder countries import more food in the winter to survive. As birds don’t have a supply chain, they must export themselves towards their food instead. While some birds have evolved to live without migration, the mass movements of birds throughout the year are one reason that birds are one of the most diverse and abundant animals on Earth.
How does climate change impact this?
It’s no surprise to anyone that the ecosystems across the globe are undergoing changes due to human-induced climate change. As migrating birds occupy multiple ecosystems throughout their life, any loss of habitat can be detrimental to their survival. Plus, as the climate warms, it is changing the important timing of when migrations happen and how long they stay in their breeding or wintering sites. This is obviously a major problem because if the climate warms so much that birds no longer choose to migrate, competition will increase and endanger many more birds. These effects are even more pronounced in Northern habitats, which are experiencing climate change at an accelerated rate.
This is why many researchers are now focusing on understanding which birds are more vulnerable to the effects of climate change with the hopes of improving conservation.
Vulnerable birds
One such researcher is Andrea Brown, a master’s Candidate at McGill University. “A bird is considered vulnerable if it can no longer reproduce and survive on its own” explains Andrea. She adds that birds “may be experiencing environmental change due to climate change or anthropogenic activities resulting in its inability to [stay] in its current environment”. This would mean that a bird species needs to either adapt to their new habitat (by the process of evolution) or move to a new area that is more suitable to avoid going extinct.
This is why her research is so important. Andrea is using specific traits, or features, along with the known distributions of Canadian bird species to predict which species should be considered as vulnerable or not. Current modelling of vulnerable birds only considers species’ annual and seasonal distributions, and so Andrea’s goal is to improve the accuracy of those models by including the specific traits that birds use for their everyday survival. For example, Andrea’s models consider bird clutch sizes (the number of eggs a bird lays). When a species lays more eggs, there is a greater chance that at least one of its offspring, or babies, will survive – making that species more resistant to climate change. Using these updated models, conservationists can pinpoint key areas for conservation projects across Canada – giving migratory birds a better chance of survival.
As we enter a time of major species loss, researchers like Andrea are improving our chances of protecting more species every day! While times may be challenging for species, not all hope is lost. Great research is underway, and if we all work together, we can keep our world a great place for all.
Interested in learning more? Check out these links or drop a question below in the comments.
- The Concepts and Terminology of Bird Navigation, K. P. Able (2003), Journal of Avian Biology 32: 174-183
- Animal navigation: how animals use environmental factors to find their way, R. Wiltschko & R. Wiltschko (2022), The European Physical Journal Special Topics.
- Phenological trends in the pre- and post-breeding migration of long-distance migratory birds, Lawrence, K. B., Barlow, C. R., Bensusan, K., Perez, C., & Willis, S. G. (2022), Global Change Biology, 28, 375–389.
- Nomadic breeders Snowy Owls (Bubo scandiacus) do not use stopovers to sample the summer environment, Brown, A., McCabe, R.A., Therrien, J.-F., Wiebe, K.L., Weidensaul, S., Brinker, D., Gauthier, G. and Elliott, K.H. (2021), Ibis, 163: 1271-1281.
- Long-Term Trends in Spring Arrival Dates of Migrant Birds at Delta Marsh, Manitoba, in Relation to Climate Change,Heather M. Murphy-Klassen, Todd J. Underwood, Spencer G. Sealy, Ashleigh A. Czyrnyj (2004), The Auk, Volume 122, Issue 4, Pages 1130–1148.
All images created with dreamstudio.ai
