The Canadian Field-Naturalist 



[Vol. XXXIII. 



The Caspian Terns' nesting ground was a com- 

 pact area situated on a slope of the shingle spit and 

 measured only some 20 yards by 30 yards. The 

 ternery sloped from some 10 to 12 feet above lake 

 level at the highest point down to some four feet 

 above lake level at the lowest point. In this space 

 were well over 200 nests. Somewhat over 400 eggs 

 were noted and exact measurements taken of 46 of 

 them. A small, peculiar pond to the west of, and 

 some 10 yards from the boundary of the ternery, 

 contained a few water plants and algae and was 

 well populated with large frogs (Rana pipiens). 

 Th-s pcnd showed every evidence of being much 

 visited by the birds. Between 600 and 800 adult 

 Caspian Terns must have been observed on the first 

 visit, the birds resting on the stones along the shore, 

 fishing off-shore or flying together with Herring 

 Gulls and Common and Forster Terns above the 

 island. The stomach of the individual shot con- 

 tained remains of small fish. The identity of the 

 species was first suspected from the size and shape 

 of the eggs, later determined by close range observa- 

 tion from 'he hiding-tent and finally confirmed by 

 the finding of dead specimens and the shooting of an 

 adult female. 



The nest frequently consisted of mere depressions 

 in the shingle, absolutely no vegetable or other 

 materials being utilized. In some other instances, 

 grass bents, dead rushes, bits of drift, etc., were 

 gathered together forming a ruds, basin-shaped 

 structure. Thus the type of nest appears to re- 

 semble most closely that of Lesser Tern (Sterna 

 m'mula) (9) and not that of the Common Tern 

 (Sterna hlrundo) (10) which most frequently builds 

 quite a noticeable nest of gathered materials. The 

 deserted and much better constructed nests of 

 Herring Gulls were occasionally used by the Cas- 

 pian Terns, apparently no additions or alteration 

 being made by the new tenants. In no case did the 

 number of eggs in a nest exceed two. Frequently, 

 there was only one egg, usually fresh, in a nest. It 

 is of interest that Van Winkle (5) records three as 

 the usual number of eggs per nest on the Gravel 

 Gull Islands, Lake Michigan, whereas we found 

 that in some cases where there were two eggs in the 

 nest, they were both in such an advanced stage that 

 there would have been ample time for the third egg 

 to have been laid had three been the normal number 

 of the clutch. 



The eggs exhibited a considerable range of varia- 

 tion in color, size and type of marking, but destruc- 

 tion by the fishermen and the crows prevented the 

 taking of a scries of measurements similar to those 

 made by Rowan, Parker and Bell (10) as was 

 originally intended. The measurement of a char- 



acteristic series of 46 eggs was fortunately secured, 

 from which the following data were obtained: 



Average length, 63.59 m.m. ; average breadth, 

 43.84 m.m.; greatest length, 72.00 m.m.; shortest 

 length, 56.00 m.m. ; greatest breadth, 46 m.m. ; least 

 breadth, 41.00 m.m. 



The two eggs of a clutch sometimes differed con- 

 siderably, though a sufficient number were not ex- 

 amined to allow of satisfactory statistical treatment. 

 Thus : in clutch No. 33 the two eggs were 70 x 46 

 and 67 X 45 m.m. ; in clutch No. 23 the two eggs 

 were 66 x 45 and 63 x 43 m.m. 



Like differences were found also in color, for in 

 one nest one egg was of a pale blue background 

 with a few very faint spots, while the second was 

 hcnvily spotted and blotched wi^h black upon a 

 brown background. The eggs that were opened 

 and examined exhibited every stage of development 

 from practically no incubation, the primitive streak 

 stage, through to large embryos. The majority, how- 

 ever, were fresh. None seemed less than a week 

 from hatching. 



THE PARASITIC JAEGER. 

 The Parasitic Jaeger (Stercorarius parasiticus) 

 of v/hich a specimen was found on July 23 on the 

 north end of Pelican Island, is also a bird of some 

 interest as it is the first record for this area. The 

 Canadian Catalogue of Birds (Macoun, 5) gives 

 the following record for Hudson Bay: "a specimen 

 of the melanistic form (of Stercorarius parasiticus) 

 taken at Fort Churchill, Hudson Bay, 1845 (Dr. 

 Gillespie, Jr.) " Prtble (7), however, records the 

 species as occurring on the coast of Hudson Bay, 

 below Cape Eskimo in 1900. Both of these, how- 

 ever, are on the sea-coast and at least 500 miles 

 norlh of Pelican Island. The two other members 

 of this strange genus, the Pomarine Jaeger (Stercor- 

 arius pomarinus) and the Long-tailed Jaeger (S. 

 longicaudus) have been recorded for Manitoba, the 

 former on Hudson Bay (Preble, 7) and the latter 

 once from Aweme, Man., May, 1903, by Mr. 

 Norman Criddle (Macoun, 1909) and also once 

 from Clandeboye, Man., October, 1902, by Atkin- 

 son (2). 



The specimen of Parasitic Jaeger which the 

 authors discovered was lying dead on the rocky 

 ground above the drift line in the midst of a de- 

 serted Herring Gull colony. The individual was an 

 example of the white phase. From the situation and 

 appearance of the bird it is possible that it had been 

 killed by Herring Gulls while poaching on the 

 colony, a fate several limes recorded for this species. 

 OTHER BIRDS. 

 The followmg observations were made concern- 

 ing other species of birds noted on Pelican Island: 

 HERRING CULL (Larus argentatus). This species 



