Birds

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/

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By Judy Ferris, Master Naturalist and Guest Blogger

Though it may be cold and windy outside as you read this, rest assured that a springtime surge of songbirds has already started moving northward. Most of our North American songbirds (warblers, sparrows, orioles, tanagers, and thrushes) head south for the winter.

Pine Warbler – This small but hardy species is one of our first songbirds to arrive in spring to breed and nest. They have already arrived this spring at their territories in southern Maryland. You may hear their warbling trills as they stake out their territories in areas of mature pines. Click on the link below to listen to the Pine Warbler’s melodic warble.

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

Why would tiny songbirds, most of whom weigh less than an ounce, undertake such a perilous migration each year? It’s all about insects. The timing of bird migration is tied to the springtime emergence of insect abundance which we experience here in North America.

Some species spend the winter only as far south as the southern U.S. Many species, however, are long-distance migrants; traveling to and from the Caribbean, Central America, and even South America. The average distance traveled by birds migrating from South America is about 1500 miles. Their journey may involve hop-scotching across the Caribbean to Florida or include a perilous 500-mile non-stop crossing of the Gulf of Mexico.

Hooded Warbler – Winters in the Caribbean and southern Central America. Crosses the Gulf of Mexico to reach the U. S.. Breeds in the eastern U.S. At ACLT, these warblers are often tucked out of sight in foliage. If you listen, however, you may hear their ringing song.

https://www.allaboutbirds.org/guide/Hooded_Warbler – Hooded Warbler singing. Not all Warblers warble!

Consider the following:

Pound for pound, insects contain 4 times as much protein as beef.
Insect organs are rich in fat – a far better energy source than carbohydrates.
Insects are the ideal fuel for migrating songbirds.
Insects are the baby food of choice for 96% of our songbirds.

Avian migration evolved about 15,000 years ago at the end of the last Ice Age. Many of our migratory warblers, sparrows, tanagers, and orioles evolved from tropical ancestors and have close cousins who live year round in the Caribbean, Central America, and even South America. The tropics have a high density of birds, so competition for nesting sites and food is intense. From an evolutionary standpoint, it was only a matter of time before independent-minded tropical birds broke with tradition and flew to the Florida or the Gulf Coast and beyond. What did they find? A cornucopia of insects and less competition for food and territory! While most tropical birds raise 2 or 3 chicks at a time, migratory birds who head north find enough insects to rear 5 or 6 chicks! The only drawback is that it gets cold in the north in the winter. So an autumn return trip to the tropics is a necessity. Migration is a risky undertaking and some birds are lost each year. In the end, however, both the tropical stay-at-home birds and the migratory birds successfully rear about the same number of offspring.

Our migratory songbirds evolved along with the plants, insects, and other wildlife that populated a North America unmarred by human activity. When these birds flew north from the tropics and reached our shores, they were greeted by pristine beaches and an endless green carpet of forests, grasslands, and wetlands which stretched from Florida to the boreal forests of northern Canada. For a hungry bird, this was a non-stop insect buffet. Stopovers for feeding, drinking, and resting were literally everywhere.

Yellow-billed Cuckoo. Winters in South America. Breeds throughout the eastern U.S. These birds are relatively common at ACLT, but are slow-moving and tough to spot. Your best bet is to listen for them as you walk the trails. Cuckoos make a variety of strange calls which you may have heard, but not known what it was. Click on the link to hear their variety of unusual sounds. Photo by Dominic Sherony CC 2.0.

https://www.allaboutbirds.org/guide/Yellow-billed_Cuckoo/sounds

Summer Tanager – Winters in Central and South America. Breeds in the southern U.S. As you hike in mature forests, you may hear this bird singing in the tallest treetops. Click on the link to listen.

https://www.allaboutbirds.org/guide/Summer_Tanager/overview

Birds today face a very different journey than that of their ancestors. Those previously pristine beaches are now lined with forests of tall condos. Vast tracts of woodlands have been eliminated. Replaced with shopping malls, subdivisions, and farmland. The wild places that remain are becoming so fragmented that they can no longer support wildlife – including insects.

Thus places like ACLT are increasingly precious. For birds who are just pausing in their journey, ACLT is a welcome rest stop. Like us humans, birds appreciate a good layover spot and will return year after year. Many migratory birds stay to breed and raise young at ACLT. This special place hosts a variety of breeding birds including indicator species such as Louisiana Waterthrush, Worm-eating Warbler, Scarlet Tanager, Kentucky Warbler, Wood Thrush, American Redstart, Prothonotary Warbler, and many others.

Other Resources

Calvert County is blessed with numerous areas to hike and explore. As you are out and about welcoming the arrival of spring, take time to pause, look, and listen. You may hear or see a bird that you never noticed before. If you take your binoculars with you, you may even have the privilege of observing these beautiful feathered creatures up close and personal. Be sure to check out the Calvert County Birding Trail link below to find additional areas to visit. Have fun and happy birding!

Calvert County Birding Trail – https://choosecalvert.com/birding

From ACLT's Website:

In 2006, ACLT member Leslie Starr completed ‘Summer Birds of the Parker’s Creek Watershed’, as the capstone project toward a Certificate in Environmental Studies from the Johns Hopkins University School of Business and Professional Studies. The primary goal of the project was to obtain information on the occurrence and relative abundance of bird species found during summer in the watershed. Field work was conducted in summers 1999 and 2004, with particular emphasis on the various habitats of the watershed. Further study of lists of bird species of concern as documented by various bird conservation organizations, including National Audubon, the US Fish & Wildlife Service, and the Maryland Department of Natural Resources, revealed that thirty-three such species have been present in the watershed during summer, of which twenty-nine are known to be or are possibly breeding. Read more and search ACLT’s bird database here.

The Birds Are Coming – Part 2

How You Can Help

The Birds Are Coming-Part 1

Part 2 Now Available Click to Read

Other Resources

From ACLT's Website:

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