By Danika Wack- Boreal Educator
Adult Female American Redstart
Fall migration has officially begun! By the time you read this article, the Lesser Slave Lake Bird Observatory will be close to wrapping up our MAPS breeding bird program and our field staff will soon be able to focus solely on the birds that have already started heading south. While some late-breeders still have eggs or young in the nest, many baby birds are now gearing up for their first migration.
One of our most commonly banded birds is the American Redstart. How can this tiny songbird, a little more than a month old, weighing less than 10 grams, make the dangerous journey thousands of kilometres to central or South America? It all starts with dedicated parents and lots of food. Parent birds will take advantage of the long summer days to feed their chicks as much as possible. American Redstart’s can feed their young every 5-15 minutes for over 18 hours a day. Once these young birds leave the nest, the male and female adults will continue to care for these fledglings, with each parent attending to half of the young (Ehrlich, et al., 1988; Sherry and Holmes, 1997). A diet of high protein insects will allow these baby birds to grow incredibly quickly. On average, they are ready to leave the nest within 9 days and fully independent within 3 weeks! This means they are ready to begin the long journey to their tropical home.
Fledgling American Redstart who has just left the nest
Once the juvenile is strong enough, it will instinctively begin to travel south without ever having done so before. The sad reality is that over half of these birds don’t survive their first migration. There are many things that make the first journey particularly dangerous. Firstly, young birds are simply less experienced migrators. Old and young birds alike will have to face incredible risk and dangers such as domestic cats, window strikes, light pollution, and habitat loss. The good news is that if a young bird does survive their first migration, the odds of making it the next time are much higher and they can have a fairly long lifespan. The oldest American Redstart ever recorded was at least 10 years old. (Sherry and Holmes, 1997)
For many of these little songbirds, the reward is well worth the risk of migration. The tropics will provide these birds with nicer weather and a buffet of insects that they wouldn’t have access to in the boreal forest during the winter. American Redstarts are insectivores so these insects are essential to their diet. They simply wouldn’t be able to survive on berries or seeds like our winter resident species. After a winter down south, these birds will be ready to make the long journey back to find a mate and raise babies of their own next spring.
If you want a chance to see some migratory songbirds up close, you can register for our Public Bird Observatory Tours on Wednesdays and Saturdays. Just call the Boreal Centre for Bird Conservation at 780-849-8240 or email info@borealbirdcentre.ca.
Citations:
Ehrlich, P., D. Dobkin, D. Wheye. 1988. The Birder’s Handbook: A Field Guide to the Natural History of North American Birds. New York, NY: Simon and Schuster.
Sherry, T., R. Holmes. 1997. “American Redstart (Setophaga ruticilla)” (On-line). The Birds of North America Online http://bna.birds.cornell.edu/bna/species/277.
