[text on screen: Ask an Expert: Top Bird Migration Questions. Dr. Kevin J. McGowan, Bird Academy Senior Course Designer. Highlights from a webinar recorded in Sept 2023. Image of two Sandhill Cranes in a marsh. Logo: Cornell Lab]
[text on screen: Why do birds migrate?]
Other people will have to know that now not all birds migrate.
Some birds simply keep in the similar position throughout the year. So if we take into accounts the birds up within the boreal woodland, the chickadees keep there all yr spherical. They are able to in finding, consider it or now not, insect eggs and little such things as that within the bark, that they may be able to in finding sufficient meals to stay them, stay them going all the way through the wintry weather. However a large number of the opposite birds feed on flying bugs or transferring bugs, and there aren’t too a lot of the ones, up in Canada within the wintertime, so they’ve to head in different places to seek out meals. Migration is nearly at all times about discovering meals. It’s to not get out of the chilly as a result of birds can live to tell the tale chilly. However there are particular inhospitable puts that they wish to go away. However it’s nearly at all times about meals.
[text on screen: What prompts birds to start migrating?]
Smartly, the item that begins chicken migration in most cases is a transformation in sunlight and what that does is that begins this type of, the, the proximate mechanism that will get the birds brains converting, other hormones being produced, and the birds can sense even very small adjustments in sunlight duration. There’s this cool time period that’s in German referred to as Zugunruhe and that suggests migratory restlessness.
[text on screen: Zugunruhe. Migratory Restlessness]
And so we will you’ll be able to watch this. And it’s been smartly studied in birds that for those who stay them in captivity, as the sunshine adjustments, as the times get smaller or longer, they begin to get antsy and so they simply roughly transfer round of their cages and so they simply need to cross someplace. And it’s simply this wish to, to head additional, to head additional, cross south, cross south, cross down, .
[text on screen: How variable is migration timing?]
In truth it’s if truth be told rather rigorous in some species. It’s very, very predictable. Like when Pink-winged Blackbirds flip up in central New York, is is at all times inside of a two week duration. And so a few of these issues are very actual. Then again, migration on, , for a person chicken depends upon the, instances that that chicken is in. And that comes with adjustments in climate and, and native stipulations and stuff like that. So there’s at all times that type of positive tuning. So it’s by no means exactly the similar.
[text on screen: Do adult and juvenile birds migrate together?]
Yeah, that’s a captivating factor about migration is we generally tend to assume, oh smartly, yeah, they only cross—However they don’t There are other… other… the sexes do various things. And the juveniles do various things. And generally what you notice going first are the men, the breeding men of a large number of other birds go away the breeding grounds ahead of the ladies or the juveniles do. After which as a… once more, as a common rule of thumb the adults go away first after which the juveniles go away later. And it can be they only desire a longer time to fatten up, emigrate. However that’s very an excessively predictable trend that we see
[text on screen: What’s the best time of day to migrate?]
[image: map of continental United States in purple, orange, and yellow against a black background, colors indicate predicted strength of bird migration. Text on screen: Migration intensity scale: white = High; yellow to orange = Medium; purple = Low; dark = None. 378 million birds predicted. Logo: BirdCast]
Other birds do migrate at other occasions of the day. And to, a large number of individuals are shocked to understand that the the majority of migration occurs at night time, that almost all birds fly at night time. And there’s a number of causes for this. One is they, , there are fewer predators having the ability to catch you at night time. You’ll be able to’t truly forage that a lot, so it’s possible you’ll as smartly fly.
[Image: graphic of a flying Yellow Warbler against a globe depicting lines of magnetic force]
When there’s now not sufficient mild to peer really well, birds can if truth be told activate a unique sense and notice the magnetic fields of the earth. And so they may be able to inform north and south, as a result of they may be able to see the magnetic fields. I learn that information and it’s like, oh, that’s why they fly at night time is as a result of then they may be able to see. And that does appear to be the consensus is that, a large number of the midnight flying, is as a result of that permits them to use their magnetic sense to discover north and south.
[text on screen: How can people help migrating birds?]
Smartly, hummingbird feeders, the hummingbirds truly like hummingbird feeders, and also you received’t cause them to prevent migrating, and keep it up and stick to your feeder until it will get chilly. They’re now not going to try this. However they’re going to use it as a supply of, affordable power that they may be able to placed on and, and, assist them alongside their means. Suet for one of the different birds is excellent. The opposite factor to do to assist birds alongside all the way through that is flip off your lighting fixtures at night time. That’s a large one. And naturally, this truly performs out within the towns. And, and there are the methods that individuals have, a lot of organizations are running with, together with the Cornell Lab of Ornithology, which might be seeking to inspire giant towns to chop down on their mild utilization all the way through top migration time as a result of birds get puzzled. And so flip off your lighting fixtures at night time, plant local vegetation, submit a hummingbird feeder. That doesn’t do all of it. However there are a few tangible issues that individuals can do.
[text on screen: Media Credits: Oregon soundscape by Todd Sanders / Macaulay Library; Sandhill Cranes by Dylan S. / Macaulay Library; Blaack-capped Chickadee by Nick Saunders / Macaulay Library; Tree Swallow by Blair Dudeck / Macaulay Library; Whimbrels by Matt Aeberhard / Macaulay Library; Red-winged Blackbirds by Ron Beurkert / Macaulay Library; American Avocets by Matt Zuro / Macaulay Library; BirdCast Migration Forecast 6 Sept 2024 / Cornell Lab and Colorado State University; Geomagnetic illustration by Jillian Ditner / Cornell Lab; Calliope Hummingbird by Joshua Glant / Macaulay Library; Nighttime view from space by NASA / JPL.]
[soundscape of bird calls ends]
Finish of Transcript