Category Archives: Nature Notes

Last Month in Birding: May 2015

Each month we take a look at a few of the previous month’s bird sightings as suggested by our experts. Here are five of May’s most exciting observations.

Little gull (Hydrocoloeus minutes)

True to its name, this bird is the world’s smallest gull. It is common across much of Europe and Asia. In North America, a few little gulls have been breeding on the east coast since at least 1960, but this bird is still a rare sight. Last month, Massachusetts birders were amazed to note this species at three locations, including at least 10 birds at Hatches Harbor in Provincetown.

Little gulls (and one Bonaparte's gull), Hatches Harbor, Race Point, Provincetown © Ryan Merrill

Little gulls (and one larger Bonaparte’s gull), Hatches Harbor, Provincetown © Ryan Merrill

“Lawrence’s warbler” (Vermivora pinus x chrysoptera)

This fascinating bird is a hybrid, the result of a pairing between a blue-winged warbler (Vermivora pinus) and a golden-winged warbler (Vermivora chrysoptera). The offspring of these closely-related birds are usually fertile, and they generally fall within two broad color categories: the grey and white “Brewster’s warbler” and the golden “Lawrence’s warbler”. The Lawrence’s is the rarest possible outcome, since its traits are recessive. Two of these stunning birds were seen in May—one in Petersham and one in West Newbury.

Lawrence's warbler in West Newbury © Margo and Steve, webirdtoo

Lawrence’s warbler in West Newbury © Margo and Steve, webirdtoo

Mississippi kite (Ictinia mississippiensis)

A graceful raptor, the Mississippi kite eats insects. It is most commonly found in the Great Plains and the US southeast, but its range has been expanding by leaps and bounds, and it is now spotted almost every year in Massachusetts. In fact, this species has even been found nesting in Connecticut, Rhode Island, and New Hampshire in recent years. The reasons for its spread are probably numerous, but here is one contributing factor: Mississippi kites like open areas with scattered trees, a landscape pattern that people frequently create. Last month, several birds were seen on the Outer Cape, and individuals were also seen in Westboro and Amesbury.

Mississippi kite, Westboro © Steve Arena

Mississippi kite, Westboro © Steve Arena

Brown booby (Sula leucogaster)

This sleek seabird lives in many tropical oceans throughout much of the world, where it executes dramatic plunge dives for its prey, especially flying fish. It is related to the famous blue-footed booby, but its feet are yellowish. It does not currently breed in the US mainland. Last month during our annual Bird-a-thon fundraiser, two participants on a whale watch trip were thrilled to spot a brown booby off of Gloucester. No doubt it was a prized addition to their lists, as well as to the whole Bird-a-thon!

Brown booby in a more tropical locale, CC BY-NC-ND 2.0 Mark Yokoyama

Brown booby in a more tropical locale, CC BY-NC-ND 2.0 Mark Yokoyama

Chuck-will’s-widow (Antrostomus carolinensis)

Perhaps you’ve heard the night call of this species’ better-known relative, the whip-poor-will. The chuck-will’s-widow breeds mostly in the southeastern US, and it is the largest North American member of the group of aerial insect-eaters known as nightjars. Despite its size, this bird is hard to spot. Its feathers match the pattern of bark and leaves. However, its namesake nocturnal “chuck-will’s-widow” call is loud and incessant. One was heard calling in East Orleans during Mass Audubon’s Bird-a-thon fundraiser.

"Chuck-wills-widow RWD7" CC BY-SA 3.0 Dick Daniels (http://carolinabirds.org/) - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Chuck-wills-widow_RWD7.jpg#/media/File:Chuck-wills-widow_RWD7.jpg

Chuck-will’s-widow CC BY-SA 3.0 Dick Daniels (carolinabirds.org)

Surprising Animal Color Variations

Every now and then you might see an animal that looks like a member of a familiar species, but with a twist: it’s much darker or lighter than normal. What’s the story behind this unusual coloration?

Melanism

A rare melantistic chipmunk, 2011 Photo Contest Entry, © Katharine Wall

Melanistic Eastern Chipmunk © Katharine Wall

Eastern chipmunks are known for their stripes, but this all-black animal is the rare exception to the rule. When creatures are much darker than is typical for their species, it’s because they have more melanin—a group of dark pigments—in their skin, feathers, or fur. The resulting condition is called melanism.

Albinism

Albino Gray Squirrel © Paula Sheehan Gaudet

Albino Gray Squirrel © Paula Sheehan Gaudet

At the other end of the scale, this eastern grey squirrel has a genetic mutation that stops it from producing melanin. Called albinism, the condition results in light-hued fur or feathers, as well as eyes and skin—note this squirrel’s pink eyes.

Leucism

leucistichawk

Leucistic Red-tailed Hawk © Marj Rines

Leucistic animals have a mutation that reduces the amount of melanin and other pigments in their fur, feathers, or skin (but not eyes). Some of them retain the typical color pattern but look faded or washed out. Others have patches of white. You may also see all-white animals with dark eyes, as in this red-tailed hawk; so long as the eyes aren’t pink, you’re looking at an example of leucism, not albinism.

Here are a few other striking leucistic birds. Can you identify them all?

Clockwise from top left: American Robin © Dawn Vesey Puliafico; Song Sparrow, Blue Jay, and Eastern Bluebird © Greg Dysart

Clockwise from top left: American Robin © Dawn Vesey Puliafico; Song Sparrow, Blue Jay, and Eastern Bluebird © Greg Dysart

Red and Yellow Variations

House Finches CC BY 2.0 Andrey Zharkikh

House Finches CC BY 2.0 Andrey Zharkikh

Creatures may also vary in the amount of red and yellow pigments they display. Genetics can play a role in these differences, but diet is also an important factor. House finches, for example, get their red coloration from pigments called carotenoids in their food. When their diet is poor in these substances, they are yellow instead of red (like the bird at the top of the picture).

Diet can also cause yellow feathers to turn orange. Cedar waxwings, for example, usually have yellow tail tips. But when they dine on invasive honeysuckle berries during a key part of the feather growth cycle, their tails turn orange.

Orange-tailed Cedar Waxwing CC BY-NC-ND 2.0 Henry T. McLin

Cedar Waxwing with Orange Tail CC BY-NC-ND 2.0 Henry T. McLin

There are many other reasons why a creature may look a little different from the one in your field guide. For example, pollution or normal wear and tear on a bird’s plumage can change its appearance. No matter the cause, these stunning variations help us sharpen our identification skills!