214 SWIMMERS. 



north as the ever-inclement shores of Greenland and Spitz- 

 bergen ; it is also found on the Arctic coasts of Siberia and 

 Kamtschatka. In the winter it migrates to the Mediterranean, 

 Madeira, and the Canary Islands. In America it breeds along 

 all the coasts of the Northern and Middle States, and pene- 

 trates north into the fur countries up to the 5 7th parallel of 

 latitude. It also breeds on the sand-bars of the Great Western 

 Lakes, being frequent in those of Erie, Huron, and Superior. 

 In short, no bird is more common along the sea-coasts and 

 lakes of the whole northern hemisphere, within the limits of 

 cool or moderate temperature. 



These Terns arrive on the coast of New Jersey about the 

 middle of' April, and soon after they are seen on the shores 

 of New England, where they are known by the name of the 

 Mackerel Gull, appearing, with the approach of that fish, 

 towards the places of their summer residence. In New York 

 they are dignified, for the same reason, with the appellation 

 of the Sheep's-Head Gull, prognosticating also the arrival of 

 that dainty fish in the waters of the State. About the middle 

 of May, still gregarious as they arrive, they commence with 

 the cares of reproduction. Artless in contrivance, the Terns 

 remedy the defect of a nest by selecting for their eyries insula- 

 ted sand-bars, wide beaches, but most commonly desolate, bare, 

 and small rocky islets, difficult of access, and rarely visited by 

 anything but themselves and birds of similar habits. A small 

 hollow scratch on the surface of the shelving rock, with the aid 

 of a little sand or gravel merely sufficient to prevent the eggs 

 from rolling off, are all the preparations employed by these 

 social and slovenly birds. The eggs are left exposed pur- 

 posely to the warming influence of the sun, the parent sitting 

 on them only in the night or during the existence of wet and 

 stormy weather. They are about i H inches long by i X in 

 width, of a dull yellowish or pale whitish olive, with dark- 

 brown blotches and spots, and others of a pale hue beneath 

 the surface, the whole often disposed in a sort of irregular 

 ring towards the obtuse end. Other eggs, again (as if of a dif- 

 ferent species of bird), are spotted almost equally all over. 



