ZOOLOGICAL REPORT. 



Ill 



the contents, to note down the exact result of this examination, with the 

 date of the observation, and to preserve those pieces in order to form, in 

 time, a collection by means of which one can in the future verify each of 

 the registered facts. This collection, commenced by me more than thirty 

 years ago, comprises, to-day, a considerable number of specimens, which I 

 have disposed of for preservation in three different ways. The first con- 

 sists of stomachs opened and dried, with their contents, then fixed upon 

 cards, which bear, besides the name of the species of birds, the locality 

 in which it has been killed or taken, the precise date, and, in fine, the 

 name of the animals or of the vegetables whose fragments can be recognized 

 in the stomach. The second mode of preservation has consisted simply in 

 putting into little corked vials the stomach or its contents ; the same mode 

 of labelling has been employed. And, lastly, I have preserved duplicates 

 of all in alcohol. 



1 have the honor of presenting to you some samples of pieces preserved 

 according to one or the other of these processes. A glance at these 

 specimens will suffice to convince one that the matter thus found in the 

 stomach of the bird is not only almost always easily recognizable, but an 

 attentive examination, executed by myself with the kind assistance of M. 

 Boulard, entomological preparer to the Museum of Natural History, has 

 also shown us that, in many cases, it is possible to arrive at great precision 

 in determining the species which serves for the food of each bird. Insects 

 offer great resources in this particular. Besides that we often find them 

 entire in the stomach, it suffices only to dilute the contents in a liquid to 

 recognize a good number of antennse, jaws, lips with their feelers, feet, 

 and often entire heads, and these fragments give the means of determining 

 the family, the genus, and in some instances even the species. I ought to 

 hasten to say, that, according to this report, the numerous collection which 

 I have made, claims still a long work ; but the materials exist, and, with 

 time, I shall do all that I can towards interpreting them. 



As to the stomachs of birds of which insects do not form their habitual 

 nourishment, their contents offer certain difficulties which it is not impos- 

 sible to surmount. Those which feed upon vertebrated animals possess 

 in their stomachs parts of the skeleton of their prey, which permit deter- 

 minations analogical to those of which I have spoken in respect to insects. 

 It is often less easy to arrive at a precision satisfactory, when the birds feed 

 upon animals destitute of hard parts ; meanwhile, as in respect to many 

 species I have been able to procure duplicates and triplicates of samples, 

 comparative observation furnishes data sufficiently complete. In that 

 which concerns the species whose alimentary regimen is vegetable, the 

 granivorous would present great difficulties, if frequently the grains found 

 in their crop, and even in their gizzard, were not perfectly susceptible of 

 germinating — a fact which always permits, as there is interest in doing it, 

 the recognition, with exactness, of the species of grain with which the 

 bird has intermeddled. I ought to acknowledge that the greatest uncer- 

 tainty exists when the stomach encloses only immature parts of vegetables. 



