The Birds Are Coming

By Judy Ferris, Master Naturalist and Guest Blogger

You may not be able to tell by looking out your window, but spring songbird migration has already begun! Songbirds were slowly pushing northward into the U.S. as early as March. The tide of migratory birds will gradually increase through April, then reach a peak here in Maryland in the first two weeks of May. This phenomenon generally occurs at exactly the same time each year no matter how good or how bad our weather is.

Northern Parula – Winters in the Caribbean and Central America. Nests in eastern U. S. and Canada. Breeds and nests at ACLT. One of our first songbirds to arrive in spring. Click on the link below to listen to its song “Pa-ruuuuLA!” You will hear Parulas in the treetops of ACLT about the time the trees start to leaf out. https://www.allaboutbirds.org/guide/Northern_Parula

In light of our recent weather, you might well ask “How do birds who winter in the tropics know when to start migrating?”. They have no idea what sort of weather we are having here. Some bird species are triggered by day length. As we move from winter to spring, the days become longer. This triggers hormones in migratory birds. The most obvious effects of these hormones are 1) polyphagia – the desire to eat lots of food! Glutinous eating ensures that the birds put on plenty of fat – their primary fuel – before they head north. 2) Sexual hormones kick in. Sexual organs which shrank last fall are now reemerging. The birds begin to feel the imperative to fly north in order to be the first to claim territory and mates at their favorite nesting ground.

Scarlet Tanager – Winters in northern South America. Nests in northeastern U.S. Breeding bird at ACLT. Click below for its song which you will likely hear from the upland forests as you hike ACLT. https://www.allaboutbirds.org/guide/Scarlet_tanager

Songbirds generally fly in mixed flocks at night. Yes, these tiny birds take off at dusk, fly through the night, then settle in at a ‘rest stop’ as dawn approaches. Why fly at night? One of the primary reasons is that it is cooler. Songbirds are totally insulated with feathers and can only dump heat through their bare legs. If they flew under the hot sun, the birds would overheat and perish. In addition, winds are generally calmer at night and there is less risk of being picked off by predators.

Veery – a member of the thrush family. Winters in central South America. Breeds and nests in northernmost U. S. and southern Canada. Uses ACLT as a stopover, then continues north. Unfortunately, Veerys don’t get into the singing mood until they reach their nesting grounds. To hear their ethereal song however, click on the link.

https://www.allaboutbirds.org/guide/Veery

How do the migrating songbirds navigate in the dark? Many birds are able to navigate via the moon, the stars, and sun. New research, published in Scientific American, suggests that birds also navigate using their own personal map of the earth’s magnetic field. It takes an understanding of quantum physics to understand the details of how this works, but current thinking indicates that some migratory birds are able to ‘see’ a ‘map’ of the earth’s magnetic field with their eyes! No one knows what this map looks like to a bird, but perhaps it explains how songbirds can mysteriously navigate to exactly the same place year after year.

Most songbirds (even hummingbirds!) fly at a speed of 20-25 miles per hour during migration. They can travel 200-300 miles nightly. Like us humans, they are creatures of habit. If they find a good rest stop like ACLT, they may use that same stopover year after year as they make their way to more northerly nesting grounds. A good stopover has plenty of food for refueling, water to drink, and a nice sheltered spot to rest before departing in the evening.

Barn Swallow – Winters in Central and South America. Nests throughout much of Canada and the U. S. including Maryland. You can listen to their chatty little song by listening to link below. https://www.allaboutbirds.org/guide/Barn_Swallow/overview

Many songbirds migrate in waves. The first wave to head north are the colorful males. They are keen to be the first to return to their nesting ground to claim a good spot. They advertise their presence with their brilliant colors and plenty of singing. They spend lots of time chasing other males away. The next wave is mostly females. Females are generally duller in color than males. They are soon paired up with males and the two start work on a nest. The final wave to arrive is the immature birds. Young birds are often a bit duller in color than the adults. The dull colors help signal that they will not be involved in scrum for territory or mates, thus protecting them from hormone-crazed adults.

Common Yellowthroat – Winters in Central America and the Caribbean – Nests in most of the U.S. and a breeding bird at ACLT. You may well hear this bird sing ‘Witchity, witchity, witchity” as you walk near Parker’s Creek. Click to hear its song. https://www.allaboutbirds.org/guide/Common_Yellowthroat

White-eyed Vireo – Winters in the Yucatan and Caribbean – Breeds in eastern U.S. Breeding bird at ACLT. This bird’s herky-jerky song, sometimes emanating from shrubby areas along Parker’s Creek, is unique and one that everyone can recognize. Click to listen. https://www.allaboutbirds.org/guide/white-eyed_vireo

Whether you are a beginner or an expert, the next few weeks are the ideal time to dust off your binoculars and take to the trails in search of birds. You may see unusual birds that merely pass through the mid-Atlantic on their way north. You may also note breeding birds arriving on territory, finding mates, and nesting. Once you have surveyed every inch of a Cardinal, or better yet, a warbler with a good pair of binoculars, you will never look at them quite the same again!

How You Can Help

Migration in today’s world is a significant challenge for birds. Birds face additional challenges by simply living in the complicated world created by us humans. Since 1970, we have lost 1/3 of our birds – an astonishing 3 billion breeding birds. Each of us, however, by changing our everyday habits, can help save these feathered treasures. The bird folks at Cornell Lab of Ornithology have compiled a list of 7 Simple Actions which each of us can take to make the world a safer place for our birds. The list is summarized on the printable page below.

To learn more about 7 Simple Actions To Help Birds and how you can make a difference, click on the informative Cornell link below. https://www.birds.cornell.edu/home/seven-simple-actions-to-help-birds/

Did you miss Part 1 of this series? Click here to read it now.
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