The Illinois State Laboratory of Natural History published early studies on the trophic ecology of birds, with emphasis on the importance of birds in controlling insect populations and the resulting benefit to agriculture.
- The Food of Birds, Bulletin of the Illinois State Laboratory of Natural History, Volume 1, Number 3, Article 4, 1st edition (Forbes, 1880)Emphasizes the relationship between birds and insects. Reports on food month by month for several common species based on examination of specimens. Summaries and economic impact are presented.
- The Regulative Action of Birds Upon Insect Oscillations, Bulletin of the Illinois State Laboratory of Natural History, Volume 1, Number 6, Article 1. (Forbes, 1883)Reports on gut contents of birds taken from an apple orchard severely infested with cankerworm in Tazewell County, Illinois in two sampling periods (May 1881 and May 1882).
- The Food of Birds, Bulletin of the Illinois State Laboratory of Natural History, Volume 1, Number 3, article 4, 2nd edition (Forbes, 1903)Emphasizes the relationship between birds and insects. Reports on food month by month for several common species based on examination of specimens. Summaries and economic impact are presented. Reprinted from the 1st edition.
Table of the food of the robin
Excerpt of charge published in Forbes' "The food of birds."
Tables of the food
Excerpt from the chart published in Forbes' "The regulative action of birds upon insect oscillations."