Bats around Chicago
Chicago, Illinois, United States
Every measure here is worked out per 5 degree square, so this covers the wider area around Chicago (40° to 45° latitude, -90° to -85° longitude, about 550 km across), not the city alone. Counts are shares of all bats records in the same weeks, so busier stations do not inflate them (methods).
Arrived in the last four weeks
- Tricolored Bat around 5 October
Expected in the next six weeks
No arrivals expected here in the next six weeks, going by last year.
Dates are last year's first regular records after at least six weeks away, with each species' own uncertainty on its page. Each species page can email you when it turns up.
Most recorded, last eight weeks
| Species | Records | Per 1,000 |
|---|---|---|
| Big Brown Bat Eptesicus fuscus | 15,696 | 249.5 |
| Eastern Red Bat Lasiurus borealis | 8,312 | 132.1 |
| Tricolored Bat Perimyotis subflavus | 2,348 | 37.3 |
| Little Brown Bat Myotis lucifugus | 527 | 8.4 |
| Hoary Bat Lasiurus cinereus | 48 | 0.8 |
| Silver-haired Bat Lasionycteris noctivagans | 37 | 0.6 |
| Northern Long-eared Bat Myotis septentrionalis | 20 | 0.3 |
| Rafinesque's Big-eared Bat Corynorhinus rafinesquii | 14 | 0.2 |
| Evening Bat Nycticeius humeralis | 8 | 0.1 |
How well this area is covered
Watched in 12 of the last 12 weeks for bats (enough records to count; unwatched weeks say nothing about absence). Active stations here in the last 30 days: 407 BirdWeather. Add a station to fill the gap.