kef, kip,or kyip
Smaller than most terns, but slightly larger than the Least Tern, the Black Tern has dark gray wings and back, and a buoyant flight on broad wings. For breeding plumage, they have a black body.
Though uncommon and local, migrants can be found on any body of water from open ocean to marshes. It is found quite frequently all over Oklahoma during times of spring and fall migration.
Some local populations are declining due to wetland degradation with cattail growth, draining and agricultural growth in wetlands, invasive or exotic fish species, lake acidification, overfishing, and pesticides. Eutrophication is another problem that will only increase, and this is caused by excess nitrogen and phosphorus obtained from fertilizer runoff. This depletes oxygen for fish, which the Black Tern depends upon for minor food sources, but it does depend a great deal upon insects. Of course, these chemicals result in excessive water plant growth and that also causes oxygen depletion for the ecology of this tern.
Black Tern
Boomer Lake Park, May 2017
Breeding habitat is in the Northern US and across Canada in small to large freshwater marshes containing emergent vegetation and areas of open water. The species nests semi-colonially in this vegetation, particularly cattail rootstalks. Muskrat houses are occasionally used, but the substrates are smaller and lower than used by Forster's Terns.
North American Black Terns migrate to northern coastal South America or to the open ocean.
The American subspecies will show as a vagrant to Great Britain and Ireland.
No comments:
Post a Comment