Two Nestling Robins with Abnormal Beaks
Two Nestling Robins With Abnormal Beaks.--The recent paper by Fox (Condor, .54,1952: 160-162) on the abnormal growth of beaks of birds prompts me to offer the following observation. . During the 1951 nesting season I found in Memorial Cemetery, Scott County, Iowa, a nest of a Robin (Turdus migratorius) that contained four nestlings that would have left the nest in another day. Of these four birds two of them had deformed beaks. The best way to describe them would be to say that they reminded one of the mandibles of crossbills (Lo&), the only difference being that when the mandibles were closed there was an opening of one-quarter of an inch between the upper and lower mandibles. The birds were able to accept food without any difficulty from the adults and were apparently in just as good physical condition as the other two nestlings. Both adults were observed through glasses and their mandibles were normal. This particular example may be just another shred of evidence to sustain the thesis that some of the abnormal beaks of birds may be genetic in origin.- JAMES HODGES, Davenport, Iowa, June 13,1952.
