NORTH AJIERICAN BIRDS. 39 



77. HydrocMidon nigra surinamensis (Gmel.) [693.] 



Black Tern. 



Hab. Temperate and tropical America, from Alaska and fur countries into South America; breed- 

 ing from the Middle United States northward. 



The Black or Short-tailed Tern is distributed throughout North 

 America at large, both along the coast and in the interior ; breeding 

 anywhere in colonies, in marshes and reedy sloughs, where it deposits 

 the eggs on dead reeds, which are often floating. It is known to breed 

 abundantly in various marshes of ]Michigan, Wisconsin, Minnesota, 

 Dakota, Oregon and California. It has exceedingly long wings, and in 

 its pursuit of insects in the air its flight and evolutions resemble those 

 of a swallow. Mr. Frank W. I^angdon observed this species to be a 

 very common summer resident of a marsh in Northern Ohio.* He 

 found it " nesting, or rather laying its eggs, on the little islands of 

 decaying vegetation and mud formed by sunken muskrat houses. 

 Three eggs constitute a full set, and they are apparently rolled about 

 in the mud purposely until well coated, so as to hide the markings, 

 and thereby make them less conspicuous." Mr. Langdon says that in 

 two or three instances an attempt at nest building was noticeable, con- 

 sisting merely of a few fragments of grasses, so disposed as to prevent 

 the eggs from rolling. Two broods are reared in a season, as eggs 

 were taken in May, and jNIr. Langdon collected fresh eggs in July. 

 They vary from brown to greenish ; thickly spotted and blotched 

 with brown and lilac of various sizes, but mostly bold, large and of 

 light and blackish brown, thickest around the larger end. They re- 

 semble some of the sandpipers' eggs in size, shape and color. Average 

 size 1. 35 X. 98. 



78. Hydrochelidon leucoptera (Meisn & Schinz.) [694.] 



'White-Tiriiiged Black Tern. 



Hab. Eastern Hemisphere; accidental in North America. 



A single example of this European species was taken on L,ake 

 Koshkonong, Wisconsin, in the first week of July, 1873. The ovaries 

 of this specimen contained small eggs. It occurs occasionally in Great 

 Britain, and is accidental in Sweden. On the lakes, rivers and 

 marshes of the countries of the Alps it is said to be very common, 

 and also in the bays and inlets of the Mediterranean Sea. Its 

 nesting and general habits are said to be like those of H. nigra 

 surinamensis. The eggs, however, as a general rule, ha^-e a lighter 

 ground color, and average slightly larger than those of the American 

 bird. 



* Summer Birds of a Northern Ohio Marsh. 



