TIME TO TRAVEL

  • Barn swallows fly in and out of a barn at the Fort River Division of the National Fish and Wildlife Refuge in Hadley on Friday, July 13, 2018. The barn remains on the site from the former Bri-Mar Stables. —Daily Hampshire Gazette

  • Barn swallows fly in and out of a barn at the Fort River Division of the National Fish and Wildlife Refuge. Daily Hampshire Gazette file

  • Five baby barn swallows peer out from their nest in the rafters of a horse barn in Chesterland, Ohio. AP file

  • Barn swallows are cared for in a barn near Lawrence, Kan., Tuesday, Aug. 2, 2011. The birds fell from their nest and were given a new home in a funnel. The parents continue to care for them. (AP Photo/Orlin Wagner) Orlin Wagner—AP

For the Monitor
Published: 9/8/2020 10:53:23 AM

Many people have curtailed travel plans this year because of COVID-19 but the virus has not interrupted travel plans for migrating birds. They are on the move. Much like people who have a wide variety of travel methods, routes and routines, migration varies widely depending on the species of bird.

The primary factor that impacts migration is diet. Birds that eat flying insects, fish or aquatic plants must leave our area because that food isn’t available or accessible in the winter. Swallows, flycatchers and many warbler species must travel to places where they can find insects. Osprey, herons and ducks travel to places where there is open water to fish or dabble for their meals. Sometimes these trips are relatively short while others cover a staggering distance. How far they need to go, in turn, impacts when they leave (and when they return in the spring).

Barn swallows, one of the aerial insectivores (birds that catch insects while flying) have mostly left New Hampshire because their final destination is in South America. They won’t return to the northeast until late April or early May.

By contrast, another aerial insectivore that builds nests on our human-made structures, the Eastern Phoebe may remain in this area until November. They stay on this continent for the winter, making a much shorter trip to the southern U.S. or Mexico. This is why they are one of the early birds that we see in spring – often in late March or early April. Shorter migration routes enable them to spend longer in the north and take advantage of the variety of insect species that also inhabit our region.

Whether short or long, it’s amazing to think about these small creatures traveling hundreds or thousands of miles, fueled solely by the guts and exoskeletons of flies, mosquitoes, moths and beetles. They feed primarily during daylight hours when the insects are more active. But they also use this time for short power naps because nighttime is when they do their traveling. If you go out when the moon is full or large, you may actually be able to see the silhouettes of songbirds flying by. Sometimes their high pitched twittering can also be heard on an autumn night. They use sound to help keep their flocks together. Navigating with use of stars and an internal compass, their nocturnal journey helps them avoid daytime predators such as hawks.

Traveling on a diet of insects is one thing, but hummingbirds migrate long distances powered by nectar and sugar water. These diminutive and delicate jewels of the air fly to Mexico and Central America. They will be departing soon (or may have done so already by the time you read this). The traffic at my hummingbird feeders lately attests to the fact that they are gorging themselves in preparation for the trip. They usually add 25-40% of their body weight before leaving, in order to have enough energy for the journey. They have been observed traveling as much as 23 miles in one day. But when they reach the Gulf of Mexico they must make that crossing non-stop – 500 miles in 18 to 22 hours. They are most successful when the wind conditions and weather are favorable. If they do make it, and also succeed on a reverse trip in the spring, hopefully we’ll be able to greet them in mid-May.

It’s a surprise to many people that birds that feed on seeds or insects in trees may also migrate. Species that breed in Canada or in higher elevations of New Hampshire, such as the Dark-eyed Junco or Pine Siskin, migrate to our region to spend the winter. Other species such as blue jays and black-capped chickadees may displace their counterparts further south. So our winter jays and chickadees may have nested further north and our breeders may be in Southern New England or the mid-Atlantic states. Why travel further than necessary? Migration is treacherous.

That’s all the more reason to marvel at the birds that are preparing for their journeys, have embarked on them already or are passing through. Keep your eyes and ears out for these travelers  and when you see them, send them good wishes for a safe journey.




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