Nature Watch: Soaring Hawks and Dancing Flies

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.

Overview

Everyone is familiar with the first touches of spring. Leaves begin to unfurl. Flower buds open and birds begin to sing. There are other signs of the new season, however, that should be as eagerly awaited as flower petals and bird song.

Sunny March days are often when farmers work their fields, exposing the dark earth to the sun.  The soil heats up, causing warm columns of air known as thermals to rise in mid-afternoons.

Bald Eagles and Red-tailed Hawks are drawn to thermals as iron filings move to a magnet. These warm columns allow the raptors to soar with very little effort. Sometimes the birds angle up or down, trying for the warmest spot. When viewed from a distance, the formation is said to resemble bubbles or food items stirred in a cauldron, leading to the term ‘raptor kettles’ to describe the activity. Sometimes a much smaller Cooper’s Hawk or Common Raven will join the soaring group. The most impressive local kettle I witnessed held 11 Bald Eagles, six Red-tailed Hawks and two ravens.

Another kettle will often form nearby, this one composed of gulls that don’t want to mix with a kettle that contains their potential predator, a Bald Eagle.

The fields around Ebey’s Landing near Coupeville are prime kettle country on sunny afternoons with light winds.

Sunny weather drives other spring activities. Dance fly swarms will be out in sunlit areas shielded from wind. These smallish insects form loose groups of males that yo-yo up and down in hopes of finding a mate. The swarms fixate on a branch or stump to keep the group orientated. In some species, the male dance fly must present a tiny insect to a prospective mate.

Coming across a swarm of dance flies is delightful. Look for them in open patches of mixed forest or along trails through open woods. Other species are aquatic and will dance over streams or ponds.

Dance flies are harmless to humans and everything else that’s larger than a gnat.

At least two species of butterflies can emerge on a sunny March day. Mourning cloaks are large butterflies with darkish brown wings bordered by a ragged yellow or cream edge. Look for them around open areas near willows, alders, or maples.

Satyr commas have a comma-shaped mark on the underwings. The upper side of the wings is orange with black splotches. Wing edges are indented in several places, giving them the alternate name of satyr anglewing. Look for these butterflies basking on sunlit tree trunks, fenceposts, or foliage near patches of their host plants, stinging nettles.

The full force of spring is yet to impact local ecosystems, but it would be a mistake to stay indoors on a sunny day in March… I certainly can’t resist the pull of soaring hawks and dancing flies.

Red-tailed Hawk by Craig Johnson.

Fauna: Red-tailed Hawk (Buteo jamaicensis)

This is our “everyday” hawk that can easily be found throughout the year.

Red-tailed Hawks are 18 to 25 inches long, with a wingspread of 4 to 4.5 feet. The sexes look alike, with the females being larger than the males. They have a darkish head, paler chest, and a dark belly band, completing the “dark-light-dark” mantra known to hawk watchers. When viewed from the back, a perched bird will show a faint whitish V. A rufous tail rounds out the field marks.

This is a species of buteo, hawks with broad wings used for soaring. The only other buteo seen in our area is the Rough-legged Hawk, a species that migrates out of the arctic and may winter here.

Red-tails prefer to hunt from the top of a tall perch, and some hunting is done while soaring. Insects and snakes are chased on the ground, with the raptor clumsily hopping in pursuit.

When prey is spotted from a perch or from the air, the hawk glides or flap-glides downward to its target.  At 10 feet away, the legs are thrust forward. The bird makes impact with one foot slightly in front of the other.  Small prey is taken to a perch, while larger victims such as a rabbit are consumed on the ground. Voles are the primary target in our area, but birds, snakes and invertebrates are also taken.

Red-tailed Hawk pairs bond for life. Nest building or refurbishing begins in late February. Usually at least two nests are constructed, with one ultimately put to use.

The clutch of two to three eggs is laid in March and incubated for four weeks. Nestlings take 42 to 46 days to fledge. Young birds are tended by their parents for up to two months after leaving the nest.

Watch for Red-tail nesting behavior in open canopied woodlots near fields.

This raptor is an integral part of our field and prairie ecosystems. They capture enormous numbers of voles which would otherwise damage the flora of the area. We shouldn’t allow their “everydayness” to overshadow the important role they play.

Western Coltsfoot by Martha Ellis.

Flora: Western Coltsfoot  (Petasites palmatus)

This species is one of the first to bloom in the spring. Its common name is derived from a related species with leaves resembling the hoofprint of a young horse.

Coltsfoot stems emerge in February, eventually reaching 1 to 2 feet in height. The leaves appear later.

Atop the stems are multiple heads of creamy white to pinkish flowers. Male and female flowers grow on separate heads; some plants only bear one sex of flowers while others produce both. Flies and beetles are the main pollinators. Satyr comma and Milbert’s tortoiseshell butterflies take nectar from the flowers and probably assist in pollination. The flowers are followed by nutlike seeds that are occasionally eaten by chipmunks and finches.

Coltsfoot leaves are large, measuring up to 16 inches across. They have five to seven lobes which are divided all the way to the stem. Young leaves are loaded with alkaloids, a defense against being eaten. I’ve never seen evidence of deer having browsed on the foliage.

Western coltsfoot grows from a creeping rhizome that can spread over a large area. The plant thrives in moist soils with partial shade. The blooming period is March through April; later the stems and leaves die back to the rhizomes.

Read more Habitchat blog posts