Preservation of Unknown Material 



When the identity of a collected specimen is uncertain, the entire animal, 

 if it happens to be a small species, such as a frog, snake, or mouse, should be 

 preserved. This can be accomplished by injection of a 4 percent formaldehyde 

 solution. For this purpose a glass hypodermic syringe of 5 cc capacity, equipped 

 with needles 1 to 2 inches long is useful. When the preservation of the entire 

 animal is not feasible, the head, feet, and tail may be removed and tied in a piece 

 of cheesecloth along with the stomach before placing in the preservative solution. 

 If the specimen is a bird, the wings should be saved also. 



The larger injected specimens should always be immersed in the preservative 

 solution with the injection holes directed upwards to facilitate the rapid escape 

 of any gases that may form before preservation is complete. The collection of 

 these gases within the specimen, in pockets from which they cannot escape, is one 

 of the most frequent causes for the development of decayed spots in improperly pre- 

 served material. 



Collection of Pellets, Droppings, and Other Material 



Pellets from owls and other birds, mammal droppings, and cheek-pouch 

 material should be collected as individual samples. Examination of individual 

 pellets, for instance, yields more accurate and complete data than bulk or lot 

 analyses. If collected in lots, special attention should be given to packing to 

 insure against disintegration. If this is done the individual pellets can be sort- 

 ed out at the time of examination. Pellets collected periodically from roosts or 

 nests should always be collected individually and the approximate date of deposi- 

 tion indicated for each. They may be placed in small glassine or paper bags and 

 stored in a dry, insect-proof container. Before being stored, however, all such 

 material should be gassed with carbon disulphide to destroy any of the numerous 

 insect pests that otherwise would soon take possession, and naphthalene flakes 

 should be added to the container. Inspections should be made periodically for 

 signs of insect infestation. 



Pellets and droppings should be collected for food habits studies only when 

 the identity of the material is positive. Droppings from known dens or pellets 

 from under known roosts or nests are the most desirable, as certain identification 

 can usually be made in such cases. 



Shipping 



When stomachs are to be shipped, or even moved from one locality to another 

 in an automobile, they should be removed from the formaldehyde and permitted to dry 

 until no longer wet on the surface. They may then be wrapped in heayy paper or 

 cloth and placed in a suitable shipping container, such as a tin can or a wooden 

 box lined with a number of layers of newspaper or other absorbent material. Ex- 

 cess space should be filled with crumpled paper or excelsior. The receptacle 

 should then be covered with an outside shipping wrapper, which should be snug and 

 firmly tied. Stomachs or other material sent to the Bureau for food studies 

 should be marked for the attention of the Section of Food Habits, Bureau of Biolog- 

 ical Survey, Washington, D. C. 



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