The males of all the Gulls with which I am acquainted, are larger than the females; and this difference of size is observable in the young birds even before they are fully fledged. In all of these, however, putting aside their sex, I have found great differences of size to exist, sometimes as much as two inches in length, with proportional differences in the bills, tarsi, and toes; and this, in specimens procured from one flock of these gulls at a single discharge of the gun, and at different seasons of the year. The colour of their bills too is far from being always alike, being brownish-red in some, purplish or of a rich and deep carmine in others. As to the white spots on the extremities of the primary quills of birds of this family, I would have you, Reader, never to consider them as affording essential characters. Nay, if you neglect them altogether, you will save yourself much trouble, as they will only mislead you by their interminable changes, and you may see that the spots on one wing are sometimes different in size and number from those on the other wing of the same specimen. If all this be correct, as I assure you it must be, being the result of numberless observations made in the course of many years, in the very places of resort of our different Gulls, will you not agree with me, Reader, that the difficulty of distinguishing two very nearly allied species must be almost insuperable when one has nothing better than a few dried skins for objects of observation and comparison? The Black-headed Gull may be said to be a constant resident along the southern coast of the United States, from South Carolina to the Sabine River; and I have found it abundant over all that extent both in winter and in summer, but more especially on the shores and keys of the Floridas, where I found it breeding, as well as on some islands in the Bay of Galveston in Texas. A very great number of these birds however remove, at the approach of spring, towards the Middle and Eastern Districts, along the shores of which they breed in considerable numbers, particularly on those of New Jersey and Long Island, as well 15-1/2; extent of wings 24; wing from flexure 7-1/4; tail 2-7/12; bill along the ridge 2-2/12. Weight 10-1/2 oz. The young birds are similar to the female, but paler, and without the green speculum.