420 DuTCHER AND Baily, Habits of the Herring Gull. I ^^ 



not certain that it was so when first placed there, ahhough it is 

 probable that the larger portion is old grass. During incubation 

 the weight of the setting bird breaks down or packs the nests, so 

 they are continually being repaired and built up around the edges 

 with new material, which is always green grass or weeds, the effect 

 being very pretty indeed. On several occasions gulls were seen 

 gathering this material in their bills. The grass is bitten off or 

 pulled up by the roots until the bird has a ball in its bill larger 

 than a man's fist. This material is gathered where it is most 

 plentiful and is usually carried by flight to the nest site. 



The bowl of the nest varies very little in size, but some founda- 

 tions are larger than others, depending somewhat upon the 

 location of the nest. The following measurements are of nests 

 selected as good types : 



No. I. Depth of bowl, three inches; from top of nest to ground, ten 

 inches ; diameter of nest at top, ten inches, at base, tvventv-four inches. 



No. 2. Depth of bowl, three inches; from top to ground, five inches; 

 diameter at top, ten inches, at base, eighteen inches. 



No. 3. Depth of bowl, two and one quarter inches ; diameter at top, 

 nine inches, at base thirteen inches. This nest was built on the ground 

 against a small side hill so that only one side had to be finished. 



No. 4. Depth of bowl, two and one half inches; diameter at top, nine 

 inches, at base fifteen inches. 



Many other nests were measured and examined, and the average size 

 of the bowl was found to be about ten inches in diameter and three inches 

 in depth. 



To obtain a fair average of the size of the eggs, measurements of four- 

 teen sets were made as follows : 



No 



