The English Sparrow as an Agent in the Dissemination of Chicken and Bird Mites

DURING the summer of 1905, while the author was engaged in making collections of various external parasites near Arcola, Ill., a large hay-barn was found in which a multitude of English Sparrows had nested. From the roof of the barn there extended upward a large cupola, the inside of which soon proved to be perfectly alive with sparrows. Numerous nestlings were found, either concealed in the some score of large, trashy nest-bundles, so characteristic of the species, and which occupied the various recesses and corners of the wooden structure, or, being now almost full-fledged, had fluttered out of the nests whence their ill spent attempts at flight had caused no small amount of concern on part of the parents. However, as is not usually the case, the sparrows evidently did not have complete possession of this veritable hatching house for their species for a few pigeons had also shared with them the use of this structure, and an examination revealed some three or four nests of these. Luckily for us collectors the cupola was provided with a trap door, so after entering the structure we were enabled to capture several of the live birds and examine them for parasites. None of these birds were killed, but a perfectly enormous number of parasites were secured, and among them was found a very great number of what seemed to be the common poultry louse, or chicken mite, Dermanyssus gallinw Redi. Later studies have fully established the correctness of this offhand determination. Since the sparrow has been recognized for some time as being one of the many hosts of an allied species (Dermanyssus avium DeGeer), for a long while I was inclined to doubt that this mite was the real mite of poultry, yet the near proximity of the haybarn to a chicken-house, which at least for some years hadbeen known to be infested with the chicken mite, strongly suggested to