Tonight, the ratio of Eastern Red Bats to Big Brown Bats recordings was 129 to 38, where last week it was an even split.  But I don’t know if it was a change in the number of bats or if the Eastern Reds just hung out longer.  Last week, the Eastern Red Bats came out early, followed by the Big Brown Bats.  Tonight, the Eastern Red Bats stayed until it was very dark.

I have no idea if the number of bats has changed or if the food sources changed.  Unlike Bird Watching, which has a long history of citizen science and great databases (eBirds, Christmas Bird Counts, etc.), there are almost no resources for bats.  There are no hot spot maps for bats for example!  Or online records of when to expect different bat species to be present in Central Park.  This is going to take time to figure out!

Tonight there continued to be a large number of bats at dusk flying around the Model Boat Pond. 

(Pale Male roosted on a building a block south of his nest.  He’s done this two other nights this week.)

My study of the bats at the Model Boat Pond in Central Park continues.  I used a flash to photograph the bats tonight.  I was able to get a few good shots of the bats.   I think it’s going to take me weeks to learn how to shoot these bats!

There were one or two Silver-haired Bats in with the mix of Eastern Red Bats and Big Brown Bats.

I’ve somehow become addicted to watching the bats at dusk in Central Park at the model boat pond.  I even invested in a Echo Meter Touch bat detector so I can see spectrograms of the bat’s echolocation sounds.  The detector is identifying (with 80% certainty) an almost even mix of Eastern Red Bats and Big Brown Bats.  The Eastern Red Bats appear earlier in the evening followed by the Big Brown Bats.

Walking around the lake and out the west side of the park, I was able to detect two more Eastern Red Bats and two more Big Brown Bats tonight.

Another day trying to capture photos of bats at the Model Boat Pond in Central Park.  They’re a lot harder to photograph than Red-tailed Hawks!

This time of year, if you sit near the hawk bench at the Model Boat Pond at dusk, you’ll see lots of Chimney Swifts feeding.  But as it gets darker, almost like magic, there are fewer and fewer swifts and in their place you’ll see bats. 

Using a “bat detector” to monitor the pitch of the echolocation sound, I discovered the bats are primarily two species, Eastern Red Bat and Big Brown Bat.