Mar., 1922 A LARGE TE RNCCOLONY IN TEXAS 39 
Even a casual glance into the air or an analysis of the sounds coming out 
of it showed one that there were several species of terns present. <A careful 
check showed eight species, and this number was not changed subsequently. 
They were, in order of abundanee, the Gull-billed (Gelochelidon nilotica), Com- 
mon (Sterna hirundo), Least (Sterna anrillarum), Caspian (Sterna caspia), 
Royal (Sterna maxrima), Black (Hydrochelidon nigra surinamensis), Cabot 
(Sterna sandvicensis acuflavida), and Forster (Sterna forsteri). We found 
them later to be all breeding with the exception of the Black Tern, which was 
evidently a tardy migrant, loath to leave these ‘‘happy hunting grounds’’ for 
the north. 
The Gull-billed Tern was far and away the most numerous, and [ hesitate 
to esthnate the population. Remembering my Green Island experience with 
the Reddish Kgrets | would certainly say that this tern was present in double 
or possibly treble the number of the Herets at Green Island. It would certainly 
be many thousand, and apparently all were breeding. We later found thai 
Fig. 15. NEST AND EGGS OF COMMON TERN. CAMERON COUNTY, TEXAS. 
, 
Photo by Robert Runyon. 
this species occupied all three islands and was the only one which did so. On 
May 16, breeding was at its height. Building had finished and all nests eon- 
tained either eggs or young. 
The nests varied in architecture greatly. Some consisted of a mere cleared 
spot surrounded by a rim of broken bits of shells, dry mud, and fragments of 
salt grass stems. Others were considerable piles of grass and mud, well dished 
at the top, and partly lined with finer salt grass. In a few of the latter class 
the rim was ornamented with bits of shell. On the western island the nests 
were arranged in more or less of a row, following the high water limit; but on 
the mud shoals they were placed apparently at random, some amid the erass 
and others in the bare spots. Full sets of eggs consisted of two or three, no 
sets of four being found. The degree of incubation varied from perfectly 
fresh eges to eves which were visibly hatching. On the 15th all youne were in 
the downy stage and were colored a dull tan which harmonized closely with 
