Last year, biologists at Long Island National Wildlife Refuge Complex in New York conducted a survey to determine which bat species call Long Island home.
As the summer sun set and people wound down from a long day of work, a team of biologists from the Long Island National Wildlife Refuge Complex and the Biodiversity Research Institute were only just beginning their workday. They walked quietly down refuge roads and trails carrying ropes, poles, and reams of mesh as fine as a hair net. The only light came from their bright headlamps. The biologists were on an important 10-day mission: catching bats.
The health of every bat species is important, but biologists were specifically interested in confirming the presence of the federally threatened northern long-eared bat. “We wanted to locate potential maternity colonies and roost sites on the refuges so we can protect them and appropriately manage the habitats they use,” said Camille Sims, the wildlife technician.
To survey bats, refuge staff and BRI scientists used a technique known as mist netting. Camille Sims, the wildlife technician, describes the mist net as as undetectable, fine netting that acts like an invisible volley ball net, gently capturing bats while they search for food. The nets are monitored continuously from dusk until midnight.
“We checked the nets every 10 minutes for bats that may have been captured,” Sims said. “As bats fly down roads and trails where the nets are set up, they hit the net and drop into a small pocket. When we find a bat, we lower the net and gently untangle the bat to retrieve it from the net.”
The biologists weighed the bats, measured their forearms and ears, determined their gender, age, species and reproductive status. Each bat was also fitted with an identification band and wings were examined for signs of white-nose syndrome, a deadly fungal disease that has devastated bat populations across North America.
Upon completions, bats were safely released back into the night sky.
During the 10-day mist netting surveys at two refuges within the Complex — Wertheim and Elizabeth A. Morton — the team of scientists caught 5 eastern red bats and 26 big brown bats at Wertheim National Wildlife Refuge and one eastern red bat and one northern long-eared bat at Elizabeth A. Morton National Wildlife Refuge. The northern long-eared bat also received a radio transmitter to track its location.
The biological team found no evidence of white-nose syndrome during the summer surveys, but they remained alert for signs of the disease. The fungus that causes white-nose syndrome mostly affects bats during the winter, but scarring on the wings and remnant traces of the fungus can be detected in the summer. The team at the Complex doesn’t know where their bats hibernate, but northern long-eared bats have been found overwintering on Long Island in crawl spaces under buildings.
In 2015 the U.S. Fish and Wildlife Service listed the northern long-eared bat as threatened, primarily due to the threat of white-nose syndrome. In the Northeast region alone, the species has declined by up to 99 percent from pre-white-nose syndrome levels at many hibernation sites.
“As someone who cares about wildlife, I am concerned about it [white-nose syndrome] and I wouldn’t want the disease to spread to the bat populations here on Long Island, so I think it’s great news that we haven’t found signs of the disease here,” said Sims.
After many long nights, the summer surveys were completed and the team could catch up on some much needed sleep – knowing that no evidence of white-nose syndrome was found in the bats they documented on Long Island.
The surveys mentioned in the blog were conducted from June to July 2017 at Wertheim and Elizabeth Morton National Wildlife Refugess. The Long Island National Wildlife Refuge Complex uses information gathered during the surveys to determine which bat species call the refuge home and identify habitat-use during migration and breeding seasons. This information is important for species protection and best habitat management practices.
To learn more:
U.S. Fish and Wildlife Service, Midwest Region Endangered Species profile on Northern long-eared bat: https://www.fws.gov/midwest/endangered/mammals/nleb/index.html
White-nose syndrome: https://www.whitenosesyndrome.org