General summary

As of the date above, the Mobile Acoustical Bat Monitoring (MABM) database contains 33381 classified calls (30176 georeferenced) representing at least 14 species, recorded during 735 surveys along 86 survey routes located at 63 unique stations (usually National Wildlife Refuges and surrounding land) from 2011 through 2017; 15 stations conducted multiple routes. MABM survey routes ranged from 0.92 to 38.75 miles in length (average ± SD: 20.7 ± 9.4 miles).

General distribution of stations

Timing of surveys

We restrict bat surveys to the window of 16 May through 31 July, inclusive. Most surveys occurred in June and the first half of July (as expected based on the protocol), but a few surveys occurred in late May or late July.

Table 1. Distribution of surveys in MABM database.
16-31 May June 1-15 July 16-31 July
3 514 185 33

Participating stations by year

These are calculated as the number of unique stations noted in the database each year. Multiple routes from a station are ignored. Do these numbers make sense?

Table 2. Number of stations participating in MABM.
2011 2012 2013 2014 2015 2016 2017
3 39 41 56 48 46 42

Survey summary

The following figure illustrates the seasonal patterns of bat calls (per mile of route) for every participating route. Note that the number of routes differs from the number of stations because some stations conduct multiple routes.

Species summary

The following table summarizes the species distribution of the 33381 calls assigned to species, as well as the number of routes and surveys on which a given species was detected, relative to the number of possible routes and surveys on which it was possible to detect it; the number of possible routes for each species reflects the species filters we applied during classification with the Bat Call ID software.

Table 3. Summary of identified bat detections by species.
Common name # routes detected (possible) # surveys detected (possible) Total # calls detected
Evening Bat 84 (86) 709 (735) 11089
Tricolored Bat 83 (86) 705 (735) 9936
Eastern Red Bat 85 (86) 688 (735) 8075
Big Brown Bat 74 (86) 411 (735) 2512
Little Brown Bat 48 (54) 256 (464) 610
Hoary Bat 38 (42) 166 (432) 504
Gray Bat 18 (17) 70 (158) 297
Southeastern Myotis 47 (75) 122 (636) 216
Indiana Bat 17 (34) 43 (314) 60
Rafinesque’s Big-eared Bat 22 (79) 32 (665) 39
Northern Long-eared Bat 15 (45) 22 (405) 25
Eastern Small-footed Bat 7 (20) 13 (183) 14
Silver-haired bat 2 (NA) 2 (NA) 3
Ozark Big-eared Bat 1 (3) 1 (30) 1