LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 311 



full}'' gliding on their long, slender wings close to the surface in 

 search of their finny prey, the tiny minnows, which have followed 

 the advancing tide into the protecting, grassy shallows. It is a 

 pleasure to sit and watch their graceful evolution in their untiring 

 efforts to secure a meal, as they quarter back and forth over the same 

 ground again and again, cutting the smooth surface of the water 

 with their razor-like bills, scaling, wheeling, and turning like giant 

 swallows, silently engrossed in their occupation for which they are so 

 highly specialized. 



SpHng. — The black skimmers arrive on their breeding, grounds 

 on Cobb's Island and in its vicinity late in April or early in May 

 but the}^ are late breeders. For several weeks they roam about in 

 large flocks or roost on the sand bars in masses so dense that they 

 blacken the ground, every bird facing the wind. When resting 

 or sleeping in such situations they squat closely or sit upon the 

 sand for hours, but if approached every bird rises to its feet and 

 simultaneously all mount suddenly into the air, flying straight 

 toward the intruder with a chorus of peculiar barking yelps ; wheel- 

 ing just in time they circle over his head, perform a series of aerial 

 evolutions, now high in the air and again close to the water, until 

 they finally settle again on the sand. Their mating performances 

 show off their marvelous powers of flight to advantage and are 

 most exciting as two or more males give chase to the coveted female. 



The coy one, shooting ashiut to either side, dashes along with marvelous 

 speed, flying hither and thither, upward, downward, in all directions. Her 

 suitors strive to overtake her ; they emit their love cries with vehemence ; you 

 are gladdened by their softly and tenderly enunciated l)a, ha, or the hack, 

 hack, cae, cac, of the last in the chase. Like the female, they all perform 

 the most curious zigjcags as they follow in close pursuit, and as each beau at 

 length passes her in succession he extends his wings for an instant, and in a 

 manner struts by her side. (Audubon, 1840.) 



NeMing. — In 1907 I spent the last week in June on Cobb's Island 

 and other islands in its vicinity where I found several large colonies 

 of black skimmers just beginning their breeding operations. On Pig 

 Island, a low, flat, sandy island, entirely devoid of vegetation and 

 barely above high-water mark during the spring tides, I found two 

 large colonies. They had chosen for their breeding grounds the 

 higher portions of the sand flats beyond the reach of high tides, where 

 numerous oyster, clam, and scallop shells were scattered about, half 

 buried in the sand, among which the eggs were not conspicuous. 

 Large numbers of little hollows had been scraped out in the sand, but, 

 even at that late date, June 24, laying had only just begun; two 

 nests were seen with one ^gg each and one with two eggs. Many of 

 the birds were already squatting on the empty hollows or were 

 busy with their courtships. They were very solicitous, flying out 

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