BIRD HABITS 309 



Economic Importance. 



1. Destroyers of harmful insects. 



2. Destroyers of weed seeds. 



3. Destroyers of harmful rodents and other vermin. 



4. Scavengers. 



5. Producers of food, flesh and eggs. 



6. Producers of feathers, .bedding, and millinery. 



7. Guano for fertilizer. 



8. To detect poisonous gases. 



9. To carry messages. 



10. To furnish enjoyment by their beauty and songs. 



11. A few destroy useful birds or other animals. 



12. Some destroy fruit or grain. 



13. Some interfere with nesting of other birds. 



For harmful species, see "Black List of Birds." 



