Black skimmer

Anatomy
The Black Skimmer (Rynchops niger) is a medium-sized, slender water bird, whose appearance is similar to that of a gull or tern. They measure between 15.7 and 19.7 inches, have a wingspan of about 45 inches , and weigh between 7.5 and 15.8 ounces. They are often referred to as tern-like in appearance, but they are truly in a class all their own.

The top of the bird is a flat black, causing the black eyes with a vertical slit pupil to be nearly invisible, and the underpart of the bird is white. The long, laterally narrow and knife-like bill, which is red at the base and black at the time is truly unique, as its lower mandible is nearly an inch longer than the top. The short legs are reddish-orange. Males are larger than females. .

Behavior
Black Skimmers are quite social, usually in large colonies, or "conspiracies", "scoops", or "embezzlements". According to the National Audubon Society Field Guide, "Compact flocks may be seen flying in unison, wheeling in one direction and then another -- showing first the jet black of the wings, then the gleaming white of the underparts." But, Skimmers forage singly or in small parties.

Their name stems from the fact that they skim the water with their lower bill when foraging. When its very sensitive lower mandible jabs a fish, its upper bill clamps down immediately to catch the fish. Tactile feeding allows them to not only fish throughout the day, but even fish nocturnally, especially at dusk and dawn, or other low light conditions such as rain or fog.

Nesting
According to AllAboutBirds.org, the mates take turns scraping their sand scrapes, or nests, which are about 10" diameter by 1" deep. The males do more and larger scraping. This is done in “an exaggerated posture (with the neck, head, bill, and tail raised) kicking sand behind them with alternating” feet. About 3-7 eggs are laid.

Habitat
Black Skimmers prefer, according to WiseGeek.com, "sandy beaches, dunes and sand bars, marsh pools, estuaries, or near shallow bays," as well as dredge material islands, but will even gather and nest on roofs, usually gravel, due to habitat loss and disturbance. Although R.M. Erwin found that Black Skimmers when compared to birds like Common and Royal Terns, were the most restricted in their habitat use, and exclusively to marsh/tidal pools, the "Shorebirds/Seabirds-Black Skimmer" (1983) report concluded "that the skimmer is best adapted to exploit prey in the shallow, smooth water along land-water interfaces." More recent reports such as,

Hunter et al. (2006) determined that black skimmers, along with other beach-nesting species, are a highly vulnerable species and concluded that population declines will continue without conservation measures to protect nesting habitats. Recreational activity, shoreline hardening, mechanical raking, oiling of adults or breeding areas following spills, beach driving, and increased presence of domestic animals are all examples of human-induced negative impatcts to coastal habitats critical to roosting and breeding skimmers.





--MickiP65 06:32, 19 March 2013 (PDT)