First of all this is not a scientific analysis. This is simply looking at the counts from the first four years the Shelbyville BBS was run (1983-1986) versus the last four years (2011-2014). I didn’t include my data because I want to discuss it at a later date. And I know there are many variables. Things like the weather and the differences in the people who previously did the route. So I’m only looking at discrepancies which jump out at me.
Following are species from the Shelbyville BBS that had either large increases or decrease between the two-time periods.
Shelbyville BBS Decrease
- ROCK PIGEON
- YELLOW-BILLED CUCKOO
- CHIMNEY SWIFT
- NORTHERN FLICKER
- RED-WINGED BLACKBIRD
- EASTERN MEADOWLARK.
Shelbyville BBS Increase
- WOOD THRUSH
- CHIPPING SPARROW
- COMMON GRACKLE
- BROWN-HEADED COWBIRD
- HOUSE FINCH.
None of the decreases were unexpected. Maybe the decrease in Rock Pigeons. My guess is the lower pigeon numbers have something to do with the lack of cattle barns. The big open kind that have cattle below and hay above. Current barns are enclosed compared to the open type used previously. No way for the pigeons to get in to nest.
The loss of the big hedgerows maybe led to the large decreases in the cuckoo and flicker. The blackbird and meadowlark from loss of pasture land. The rest of the grassland birds had low numbers at the start of the survey 40 years ago.
The biggest surprise was the dramatic increase in Chipping Sparrows. I’m guessing it has something to do with the increase in new houses with well-manicured lawns and Bradford Pear Trees. Those houses and lawns were not there 40 years ago.
The other surprise was the increase In Killdeer. They were everywhere when I ran the route. Different farm practices make nesting better?
The Wood Thrush was almost non-existent in the early years and seemed to be present in almost every large wooded stop. The other increases were to be expected.
If your interested the complete results are at the USGS webpage.
Next post I’ll review the results from the Milroy BBS.