154 



THE OOLOGIST 



the outer margin where the ground 

 was uncovered and even dry. 



The Black Terns soon excited my in- 

 terest. To and fro over the water they 

 passed in their swallow-like flight, ut- 

 tering their sharp squeaks, and now 

 and then hovering a moment above a 

 particular spot before they dropped to 

 the surface to pick up a floating morsel 

 which pleased their fancy. Out on the 

 dry punkin vines and on the lily pads 

 they would congregate in small groups, 

 and their antics while courting were as 

 amusing to watch as those of the Flick- 

 er, though they are less noisy than the 

 latter species. Stepping out from the 

 group of six or eight, two — doubtless 

 male and female— would bow their 

 heads to each other and flutter their 

 wings in a comical way, while the oth- 

 er individuals would stand apart and 

 solemnly watch the scene. No nests 

 wei'e to be found at this time, but on 

 June 8th we found them nesting, most 

 of the eggs being somewhat incubated 

 then. Though I had never taken the 

 eggs of this species, we found them 

 readily, so that I came to regard the 

 eggs of the Black Tern as being very 

 easy to discover. If the collector will 

 be guided by the actions of the birds, 

 he will be led to the eggs as surely as 

 the birds are nesting. Like children in 

 their play of "hide the thimble," the 

 old birds hover over one's head or fly 

 about the spot uttering "hot" or 

 "cold," and when the collector is clos- 

 est to the eggs the cries of the birds are 

 sharpest and the menaces of the par- 

 ents most alarming. Then the birds 

 have a habit of hovering above their 

 eggs in company with several of their 

 fellows, and they will frequently alight 

 on their eggs for a few moments, soon 

 to arise aud fly to and fro before re- 

 turning to again reveal their homes. 

 Unless the collector strikes the swamps 

 right in the place thev are chiefly in- 

 habiting, they do not especially notice 

 his approach,* but as he nears their 



quarters individuals will now and then 

 fly over his head and protest against 

 his progress. If he strike their nesting 

 domains at once, be will be met with a 

 din about the ears which he little an- 

 ticipated if not acquainted with the 

 habits of the Terns. Soon they become 

 accustomed to the presence of the in- 

 truder and continue their tireless 

 flights up and down the open water, 

 though the owners of the nearest nests 

 continue to tell their interesting story, 

 dashing at his head with -angry cries 

 and turning upward abruptly just as 

 he expects to be struck. As the birds 

 flit to and fro, the observer can approx 

 imate the focus of their flight and if 

 they hover at that point, he may be 

 certain that they have eggs beneath for 

 his tinding. Over a small area, several 

 acres in extent, I once observed two 

 pairs of birds fli'ing and I found both 

 nests in a few minutes, guided solely 

 by their cries and hovering. I at first 

 failed to locate the second nest and 

 thought that I had been mistaken, 

 when the hovering of the bii'ds induced 

 me to return and I found the eggs on a 

 deserted nest of the Grebe, well-con- 

 cealed along the over arching flags 

 whei'e it was anchored, and nothing 

 but the actions of the birds would have 

 disclosed the nest to me. None ot the 

 eggs we found were roiled in the mud 

 or decaying matter, as I had read that 

 they often are, though most of them 

 were rather advanced in incubation 

 and I think that I was slow in finding 

 my first eggs because I looked for mud- 

 covered eggs. The ordinary sites of 

 the nests were the collapsed houses of 

 the muskrats, now floating or anchored 

 with their highest part about three 

 inches above the water level. Gener- 

 ally no nests were made, though fre- 

 quently several short pieces of the 

 punkin stems had been scratched 

 around the eggs to prevent their roll- 

 ing apart aud a ijcrceptiblo (yet scarce- 

 ly) depression had been made or found 



