About
Bird monitoring has played a crucial role in estimating population trends, distribution, and abundance for many species, and these estimates have, in turn, been integrated into management and conservation decisions for many high-profile species. These changes in management and conservation efforts have restored and stabilized many species that were once extirpated or nearly extirpated.
However, while current monitoring programs, such as the Breeding Bird Survey (BBS), Spring Bird Count (SBC), and Christmas Bird Count (CBC), have done an excellent job of estimating population trends for most species, they cannot estimate trends for nocturnal species. Because of this void, many organizations throughout Canada and the United States have begun, or are beginning to implement, monitoring programs for various nocturnal species. Initiating efficient, statistically powerful monitoring programs for nocturnal species will enable us to detect small population changes over shorter time periods.
Owl and Nightjar Status in Illinois
In Illinois, we have five confirmed breeding species of owl:
- Barn Owl
- Barred Owl
- Great Horned Owl
- Eastern Screech Owl
- Short-eared Owl
And we have three confirmed breeding species of nightjar:
- Chuck-will’s-widow
- Common Nighthawk
- Whip-poor-will
Within these two groups, the Barn Owl and the Short-eared Owl are currently listed as endangered. The Eastern Screech Owl is found in low numbers on BBS routes (BBS data); the Great Horned Owl is widespread, and the Barred Owl, which was historically listed as rare, is now found throughout the state.
As nightjars go, in 1934, Ford et al. were quoted as saying this of the Whip-poor-will in Birds of the Chicago Region: “A fairly common summer resident. Although not so numerous as formerly, they still occur throughout the area.” Unfortunately, the same cannot be said today. Common Nighthawks have a pretty even distribution throughout the state, and the Chuck-will’s-widow is found in the lower southern portion of the state. Loss of habitat, cattle grazing, and available food are all factors that could be contributing to the decline of these species.
Because much of Illinois has become agriculturally dominated, habitat selection for owls and nightjars is limited. Additionally, changes in agricultural practices have reduced the availability of food sources for owls and nightjars. Needless to say, it became apparent that Illinois needed a monitoring program that would eventually allow us to learn more about these two groups of species and the actions we need to take to conserve them.