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During the summers of 2012 and 2013, Camas Refuge has been participating in an acoustic bat inventory project. This project has consisted of setting out an acoustical bat monitor (Pettersson D500x) in various locations on the refuge during the summer months, for one week at each site. Sites selections were determined by a grid protocol, and focused on water features, where bats tend to forage or commute. The Pettersson bat monitor was set to record calls starting at sunset and running 3 1/2 hours each night.
The Pettersson bat monitor detects full-spectrum ultrasound with a microphone and records it to a CF flash memory. This data is interpreted by sophisticated automatic species identification software called SonoBat.
Results of the inventory are listed in the table below:
|
Common Name
|
2012
Count of Bat Passes
|
2013
Count of Bat Passes
|
Total
Count of Bat Passes
|
|
Long-eared Myotis
|
1
|
|
1
|
|
Western Red Bat
|
3
|
|
3
|
|
California Myotis
|
3
|
1
|
4
|
|
Yuma Myotis
|
49
|
1
|
50
|
|
Hoary Bat
|
43
|
13
|
56
|
|
Small-footed Myotis
|
12
|
112
|
124
|
|
Big Brown Bat
|
24
|
101
|
125
|
|
Silver-haired Bat
|
79
|
248
|
327
|
|
Little Brown Bat
|
2003
|
806
|
2809
|
*There were numerous other calls that at this time have not been identified to species.
The Refuge finished up this project in July, but has continued to deploy the Petersson for the last couple of months in the shelterbelt area around the headquarters to gather more information about bat numbers and species. We have been running the bat monitor all night to see when the high activity times are and to see if we have missed any species that may be more active during the early morning hours.
In the future, we hope to use this monitor to help us understand when bats are using the refuge, what bats are coming through the area during migration and get a good baseline inventory of bat species for the refuge.