Can you feel it? Nature is going through a change. It’s in the air, the ground, across the sky. The subtle creep north of dawn as it adds minutes of daylight. A south breeze that feels and smells different than a north wind. Bird songs floating through the air. Time for “Zugunruhe,” that migratory restlessness period that prompts migration.
Our lives in comparison are rather static. Many of us set an alarm to wake up and begin a day of routines – from coffee to breakfast to shuffling out the door. Hungry? Open the frig and there’s food. Sleepy? Just go to another room to bed. Such predictability is comforting, less stressful. We can do this all year long in one zip code.
March is the start of migration, a time of the most challenging changes for birds. Each year billions of birds fly great distances to mate, breed and raise their young in areas of greater plenty. Their timing and how they manage it keep scientists and birders intrigued and busy watching. Such a journey is very energy intensive requiring almost constant flying, often at night, and finding some good stop-over places to replenish calories for the miles ahead. And as the climate changes, things change below at ground level, and the burning question is, how will that impact the birds as they migrate?
During the last week of February Canada geese loudly announced their arrivals after wintering as far south as Texas and the gulf states (at least 1,200 miles away; they are capable of flying 1,500 in a day). Breeding range is as far north as the Arctic Circle (and Alaska) so many are just passing through along with other waterfowl. Ditto for the sandhill cranes that are also following the Mississippi flyway.
Juncos and tree sparrows will leave us and head north while robins will arrive from points south to Texas Hill Country (my old stomping grounds), https://journeynorth.org/robins. Along with cedar waxwings huge combined flocks gobbled up berries during winter (as many as 500-600 berries/day/bird). As they head north, berry diets give way to ground invertebrates for robins while cedar waxwings switch to the early forest tent caterpillars plucked from tasty new leaf buds in the scattered woodlands. However, if trees leaf-out too early the birds who follow a sun clock could miss out on the food needed. What if a late freeze killed the caterpillars? Or urban sprawl took out the woods? All impact the return of thousands of birds each year. They can’t “check ahead” for alternate routes.
Spring Robin, photo by Linda Oeffling
House finch and golden finches may stay or head farther north. Eastern bluebirds sometimes overwinter here but many are short-distance migrants returning from more southern states, arriving in early March. This cavity nester gets help from human fans who put up nest boxes and monitor them to keep out predators and usurpers such as the non-migratory house sparrows. But bluebirds need food for their young as well, and that means LOTS of ground level caterpillars and grasshoppers for 16-20 days. Like many nestlings, the clutch of 4-5 youngsters need to eat every 20 minutes, keeping parents busy from dawn to dark during a nesting cycle of 5-6 weeks.
While conservation lands such as Hackmatack NWR and partner sites provide protected habitat, each breeding pair of the different bird species have their own habitat needs: a particular combo of the right kind of space to find food, shelter and water. A bluebird couple’s ideal homesite is 2.5 acres of open short grassland with some trees!
Realistically, anyone with even a small yard can potentially provide habitat for at least 1 pair of birds. Scout out for cavities in trees (especially dead trees). Woodpeckers are the wild “housing developers” opening up holes for their nests that are reused by other cavity nesting birds: https://nestwatch.org/connect/news/cavity-nesting-birds-poster/. Watch to see if someone moves in between now and May. Or you can add bird houses (man-made cavities); keep in mind that size and hole diameter is important as is location for the different species: https://nestwatch.org/learn/all-about-birdhouses/.
Wildlife friendly yards help link the protected wild lands that alone cannot support all the birds (and other creatures) with adequate amounts of space to meet all the different needs. Birds don’t want to fly too far to find food for their young. So lend a hand this year, add some local native plants in your yard and experience the wonders of changing times. https://homegrownnationalpark.org/
Migration continues into May as the long-distance songbirds from Central and South America come our way. Some will make the 600-mile non-stop flight over the Gulf of Mexico. Many of the warblers will continue up to the boreal forests. (And note that migration south can begin in August!)
This massive exchange of billions of birds across and between the Americas is beyond impressive. On February 28 at 12:35 am EST, an estimated 11.3 million birds were in migration across the US while we were sleeping – and that’s not peak numbers. You can follow the action on radar maps: https://birdcast.info/. You can also add your sightings to ebird or Journey North: https://journeynorth.org/ that also tracks different species.
For me, migration is a reminder that Earth is ever dynamic, and it is not ours alone. It inspires me to be a better wild neighbor.