192 



THE OOLOGiST 



110. A. O. U. No. 748. Regulus sa- 

 trapa, Golden-crowned Kinglet. One 

 seen in our yard in Arcadia Oct. 20, 

 1921. 



111. A. 0. U. No. 751. Polioptila 

 caerulea caerulea, Blue-gray Gnat- 

 catcher. A pair seen in Arcadia Sept. 

 18, 1921. 



112. A. O. U. No. 761. Planesticus 

 migratorius migratorius, Robin. Many 

 seen in spring and fall. 



113. A. O. U. No. 766. Silia sialis 

 sialis, Bluebird. Often seen at all 

 times of year. 



Logan I. Evans, 

 Arcadia, Florida. 



EVIDENCE OF THE BLACK-BILLED 



CUCKOO ROBBING OTHER BIRDS' 



NESTS, AND SOME SCIENTIFIC 



FACTS CONCERNING THE 



COLORATION OF BIRDS 



EGGS 



By J. Warren Jacobs, Director Museum 

 of Applied Oology, Waynesburg, Pa. 



In the section of abnormal eggs in 

 the Museum of Applied Oology is re- 

 corded a set of three eggs of the 

 Black-billed Cuckoo (Coccyzus ery- 

 throphthalmus), one of which is )or 

 rather was) a supposed runt about 

 the size and shape of a Chipping Spar- 

 row's egg (Spizella passerina passej- 

 ina). The set was collected June 10, 

 1897, by the late William L. Kells, the 

 well known and very reliable Oologist 

 of Listowell, Ontario, Canada, of the 

 80's and 90's. 



At the time of receiving this set as 

 an example of abnormalism, I write Mr. 

 Kells stating my belief that the small 

 egg was an almost immaculate speci- 

 men of the Chipping Sparrow species, 

 which, in some manner, had gotten in- 

 to the Cuckoo's nest, possibly by the 

 latter species stealing the same from 

 a nearby nest of the Chippie, as the 

 Cuckoo's nest was found in an apple 



orchard wherein is usually found a 

 nesting resort of the Sparrow. Evi- 

 dence of this, I pointed out to Mr. 

 Kells, was apparent from the fact that 

 he blew the contents of the small egg 

 through a small irregular hole already 

 in the side of the shell when found. 

 This shell puncture resembles a break 

 made by a bird's beak. 



Mr. Kell's reply to me seemed too 

 positive of self assurance that the 

 small egg was of the Cuckoo's laying, 

 and the matter was laid aside for 

 future investigation. Had this small 

 egg been in the ordinary spot- 

 ting of a normal egg of the Chippie, I 

 could have been without any doubts 

 of its identity, and perhaps Mr. Kells 

 would have arrived at the same con- 

 clusion before sending me the set, i e, 

 that the small egg was really one of 

 the Chippie stolen by the Cuckoo. 

 Had the egg lacked traces of spottings 

 of a reddish pigment I could have ac- 

 cepted Mr. Kells' assurance as to 

 species, as the ground color was of 

 the same shade of green as seen in its 

 two companions — the Cuckoo's — one of 

 which also showed the same contour 

 characteristics. The markings re- 

 ferred to are of a very subdued vi- 

 naceous, or vinaceous-pink, and seated 

 most heavily in the form of an irregu- 

 lar wreath around the larger end, just 

 as the under colors are sometimes 

 seen in the lightly marked specimen 

 of Chipping Sparrow egg, and this 

 alone seemed to me, was positive evi- 

 dence that no Cuckoo laid the egg. 



In the twenty-five years which have 

 elapsed since receiving this set into 

 the Museum, I have somewhat ad- 

 vanced my own knowledge of the facts 

 governing the coloration of birds' eggs, 

 through studies of relationship of 

 birds and the causes of abnormalism 

 among eggs. Mr. Kells had based 

 identification of the small egg on the 

 fact that he found it in the Cuckoo's 

 nest, and attended, together with the 

 other tWQ eggs, by the brooding 



