Signs of the season springing up all over the watershed
What comes to mind when you think of signs of spring? Robins, crocuses and tulips?
Explore a little and you'll discover an explosion of plants and animals: Forests, fields, ponds, rivers and even the sky -still and gray through the winter months - now burst with activity, sound and color.
In waterways, a transformation is taking place. Prompted by rising temperatures, fish like the blueback herring (Alosa aestivalis), alewife (A. pseudoharengus), hickory shad (A. mediocris) and American shad (A. sapidissima), journey from oceans to rivers to spawn.
What's really amazing is that these fish return to the same area in which they were born. How they accomplish this remains a mystery. Many scientists believe that this homing instinct may be due to an uncanny sense of smell and sensitivity to magnetic signals, polarized light and unique characteristics of the natal stream or waterway.
True to its name, the blueback herring is silver with a bluish back. The alewife is silver with a bronze-green back. In both species, the silvery scales scatter light and their visibility to predators. They also share a single dark shoulder spot and vary in length from 12â€“15 inches when fully grown.
The onset of spawning is related to water temperature and length of daylight. Alewife spawn from March through April in slow-moving sections of streams. Blueback spawn from mid-April through late May and favor swifter water.
Shad are larger than river herring. American shad, about 29 inches long (maximum), are silvery white on the sides and either green or blue above, which fades to brown as they migrate. They sport one large spot behind the gill followed by several smaller spots.
Hickory shad are a little smaller (maximum length about 23 inches), and are distinguished by a prominent lower jaw. They are gray-green along the back with iridescent silver sides and bellies.
Like the herring, shad leave the ocean and return to the waters in which they were born. Both shad species generally spawn from March through June. All these fish attract another event: the arrival of the U.S. angler on rivers throughout the watershed.
Many other spring messengers are found in the understory of woodlands, including the creamy white blossoms of the serviceberry tree (Amelanchier spp.). There are about a dozen serviceberry species native to the United States.
In the East, they are also known as shadbush because they flower around the same time that shad are spawning. These flowering shrubs and trees attract early-pollinating insects. Their sweet,
reddish purple fruits are an important food for songbirds, squirrels, bears and other woodland wildlife.
The eastern redbud (Cercis canadensis) is another early bloomer. Flowering from April through May, the redbud provides lush pink to lavender hues to the landscape while other trees are still bare. On the ground are a variety of violets (Viola spp.) with white, yellow, lavender blue or purple flowers, depending on the species.
Throughout the Northeast, spring rains are creating temporary pools in woodlands and meadows known as vernal pools. Vernal pools - sometimes small and inconspicuous - explode with activity as frogs and toads call to attract mates and breed.
Wood frogs (Rana sylvatica) migrate to vernal pools early in the spring. Their call is a hoarse clacking sound, reminiscent of a quack. The wood frog is an explosive breeder, usually laying a large mass of eggs in a few days and leaving soon after.
Spring peepers (Hyla crucifer), a tree frog, follows the wood frog by a week or two. Its unmistakable mating call, the peep, and large geographic range makes the spring peeper one of the most familiar frogs in North America. The mating call can sometimes be heard up to a half mile away.
The habitat of the American toad (Bufo americanus). ranges from mountains to backyards. They are found wherever there it is moist with plenty of insects to eat and shallow waters in which to breed. Despite their warty appearance, their mating call is a pleasant musical trill.
As landscape greens up and trees and flowers blossom, there is an explosion of worms, spiders and insects. And right on their heels come migratory birds.
Migratory birds nest in North America. Because these birds eat food that is not available in winter (like insects and pollen), they migrate to South and Central America, Mexico and the Caribbean during the winter. As spring returns to North America, so do the birds as they follow their food sources to their breeding grounds.
More than 360 species of birds make this annual migration including songbirds (warblers, thrushes, tanagers and vireos), some raptors (hawks, kites and vultures) and a few waterfowl (wood ducks and teal).
Some of these birds are common to us: osprey (Pandion haliataetus), American robin (Turdus migratorius), eastern bluebird (Sialia sialis), ruby-throated hummingbird (Archilochus colubris), gray catbird (Dumetella carolinensis) and barn swallow (Hirundo rustica). Others, such as the red-eyed vireo (Vireo olivaceus), scarlet tanager (Piranga olivacea), prothonotary warbler (Protonotaria citrea) and wood thrush (Hylocichla mustelina), may be familiar only to bird watchers.
Like frogs and toads, birds sing to attract mates. The bold spring colors of males also help to entice females. Birds add color, song and aerial displays as they prepare for nesting.
Sites for Spring Sights
For information about springtime wildlife, check out these websites:
Native Plants for Wildlife Habitat & Conservation Land-scaping: www.nativeplantcenter.net
North American Amphibian Monitoring Program: www.pwrc.usgs.gov/naamp/
- Category: Wildlife + Habitat
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