Plate XL VII 



Fig. 7. HYDROGHELIDON LARIFORMIS SURIN/\MENSIS~~Black Tern. 



In Northern Ohio the Black Tern is a common summer resident. In other parts of the State it is 

 an irregular spring and fall migrant, and possibly rare summer resident, frequenting the rivers, creeks, 

 canals, and ponds. It may possibly breed about the large reservoirs and rivers in the central and 

 southern portions of the State, but I know of no instance where its nest has been taken south of the 

 Lake Eric marshes. Two broods are commonly hatched by each pair during the season. The first set 

 of eggs is laid in May, the second in July. 



LOCALITY: 



Like the Long-billed Marsh Wren, the Black Tern resorts to large marshes for the purpose of nest- 

 ing. The site chosen for the home is often a long distance from shore, upon a muskrat house, a little 

 island of matted reeds and grass, or any floating vegetable debris of the marsh. At other times it is 

 upon the ground along shore, or even, perhaps, some distance from the marsh, on the bank of a stream. 

 Usually the site is surrounded by water several feet deep. 



POSITION : 



The only point about which this bird seems particular in selecting a position for the nest is that the 

 little patch of muddy ground or decaying vegetable debris chosen for the eggs to rest upon shall be well 

 exposed to the sun's rays, the heat of which probably plays an important part in incubation. 



MATERIALS: 



r\ T o materials are carried by the Black Tern for its nest, nor does it very often make an effort to 

 arrange the materials about the chosen location. Sometimes it will elevate a little mud or decayed bits 

 of reeds slightly above the surrounding surface, and, upon this elevation, which is a little concave on top, 

 deposit its eggs. The numerous suitable positions for the eggs to rest upon in the localities selected for 

 breeding-grounds, make unnecessary any effort upon the part of the bird to construct a nest. 



EGGS : 



The complement of eggs in the first set is three, in the second set it is often one less. The ground- 

 color varies in different specimens from a light wash of a yellow-brown to a rich olive-o-reen, less fre- 

 quently it is coffee-brown of various shades. The most frequent color is perhaps an olive-tinted yellow- 

 brown. The markings consist of bold blotches, spots, and speckles of sepia so heavy as to appear black. 

 Some eggs are marked principally with large distinct blotches and spots, some have only small spots and 

 speckles confluent about the base; others present various combinations of these extremes. The deep shell- 

 marks show a bluish tint upon light ground-colors. When the eggs are taken from the nest all markings 



159 



