Friday, July 2, 2010

Keys to the Kingdom

[Glossy Ibis, Snowy Egret, and Great Egret (right, hidden) at nesting colony on "Bird Island," near Somer's Point during last night's boat trip. Click to enlarge photos.]

CMBO sponsors many boat trips to explore the back bays for good reason. Boats are the keys to the back bay kingdom, bringing you where birders otherwise can't go - close to nesting herons, egrets, terns, gulls, shorebirds, salt sparrows. . .the panoply of salt marsh bird life. Last night's trip out of Somer's Point on the Duke O' Fluke is a fine case in point. The full list is up on Field Trip Reports; all images are from last night.

[American Oystercatcher parent (left) and chick. Unlike many shorebird species, e.g. Piping Plovers, where chicks can obtain their own food, American Oystercatcher chicks depend completely on their parents for food for two months or more, because they need help not only finding food, but haven't grown bills sufficiently strong to excise mollusks from their shells.]

[If we only had a dollar for every time someone asks how to tell Common Tern from Forster's Tern. It's a fair question, since this is one of the tougher i.d.'s, in a league with Sharp-shinned vs. Cooper's Hawk. The nesting colony west of Longport has plenty of Commons to practice on. We often emphasize that Common Terns, like this one, are gray below in breeding plumage, not white. With a view like this, from a boat looking straight overhead, you can use a "cheater's" field mark - the dark on the outer tail feather of Forster's would be on the innner web, not outer. Just like any tough i.d., it's best to use multiple characters with the medium sized terns.]

[You can tell this is a Yellow-crowned Night-heron by plumage, but night-herons, being, well, night-herons, are often seen as sillouettes. A great clue is leg length - Yellow-crowned's legs are long enough that the entire feet and part of the leg extend beyond the tail as they fly by. . .]

[while Black-crowned Night-herons are short-legged, and only part of the toes reach past the tail tip. Compare the photos.]

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