Do you have bats roosting in your bat box, your barn, or at your house on Martha’s Vineyard?
We are very interested in hearing about your spring/summer bat roost or any place where you have seen bats in winter on Martha’s Vineyard.
Please email Liz Baldwin with information about your bat roost: LizB@biodiversityworksmv.org
Gathering Critical Information for Recovery and Management of an Imperiled Species
Bats play a very important role in many ecosystems by controlling insect populations, which is a valuable service to humans. For example, one bat can consume up to 3,000 small insects a night, and some of these insects include mosquitos and crop pests. Historically, northern long-eared bats (Myotis septentrionalis) were one of the most abundant bat species in New England. Tragically, their populations have declined by 95% in the Northeastern U.S. since the arrival of a cold-loving fungus (Pseudogymnoascus destructans) in 2006 that colonizes the muzzle or other exposed body parts of bats during winter hibernation. The fungus causes white nose syndrome (WNS) where infected bats exhibit unusual behavior during winter such as flying outside of hibernacula during the day, or clustering near the colder entrances of hibernacula. This unusual winter activity uses limited energy reserves and most infected bats die at or outside of winter hibernacula. WNS has killed over 5 million bats since it arrived in the northeastern United States, and it typically kills over 90% of bats in each hibernacula. Thus, our forests and fields are missing the important insect predation services bats typically offer each summer as they forage and roost in the Northeast. The estimated value of bat predation on insect pests in the agriculture industry was $23 billion annually.
Islands of Hope
While many biologists in the Northeast were reporting dismally low numbers of Northern Long-eared Bats (NLEB) in their states, a glimmer of hope surfaced on Martha’s Vineyard in 2012. In August of 2012 and 2013, The Nature Conservancy (TNC) stewardship staff at the Hoft Farm Field Station found roosting NLEB in blue bird boxes during bi-weekly checks. In summer 2013, BiodiversityWorks began collaborating with the Northeast U.S. Fish and Wildlife Service to learn more about the status of NLEB on MV. We deployed a bat detector at sites where Kendra Buresch detected NLEB during her M.S. thesis study in 1997 and 1998. The acoustic data we recorded showed echolocation calls in the appropriate frequency for NLEB at several sites in July and August of 2013, as well as at the Hoft Farm. We have continued to detect NLEB at multiple sites around the Island in the spring, summer, and fall.
Coastal areas in the Northeast (Martha’s Vineyard, Cape Cod, Nantuckey, and Long Island continue to have small breeding populations of Northern Long-eared Bat. BiodiversityWorks has been collaborating with the Fish & Wildlife Service (FWS), local landowners, conservation groups, and Zara Dowling at UMass Amherst (IGERT PhD candidate) to study these remnant populations. We have been documenting their current distribution, locating maternity colonies and assessing productivity, attaching nanotags to females to document roost characteristics during pup rearing, and using nanotags to track movements of NLEB during the fall to determine if they remain on the Vineyard or leave. Sheriff’s Meadow Foundation and The Nature Conservancy allowed us to set up temporary nanotag tracking towers that allowed us to determine whether or not tagged bats left the Island.
2014 field season
Mist nets are fine nets with a 1.5-inch mesh that biologists set across footpaths or bodies of water in areas where bats are known to forage. Free flying bats are captured when they fly into the net and become tangled. Biologists monitor the nets for bat captures every few minutes and carefully extract the bats. Bats are marked with tiny tags, measured, weighed, and identified by species and gender and then released at the site of capture. Nets are removed at the end of each night of trapping as they must be disinfected per WNS protocols. We captured breeding female NLEB at sites in Vineyard Haven, West Tisbury, and Chilmark. We also documented a juvenile NLEB roosting in a deck umbrella in Aquinnah in September. After documenting the presence of breeding NLEB in several locations, we were ready to plan for a larger field effort in 2015.
2015 and 2016 Field Seasons
Between June and October 2015 and 2016, our Northern long-eared bat (NLEB) project focused on daytime roosting and migration behavior, using nanotags (tiny transmitters) to track individual bats. This study was funded through the Martha’s Vineyard Vision Fellowship and we are collaborating with the U.S. Fish & Wildlife Service, the USGS Cooperative Research Units at UMASS (Amherst) and Virginia Tech, BOEM (Bureau of Ocean Energy Management), and Mass. Fish & Wildlife. Locally, we have permission from The MV Land Bank (MVLB), The Nature Conservancy (TNC), Sheriff’s Meadow Foundation (SMF), Vineyard Conservation Society, and Vineyard Open Land Foundation (VOLF) to capture and study bats on their properties. Several private landowners also granted us permission to study bats on their properties.
In June 2015, we captured and attached nanotags to 3 pregnant female Northern Long-eared Bats near Cranberry Acres and the Hoft Farm Preserve. These females led us to roost trees (red maple, white oak, black oak, beetlebung, sassafrass, black locust, and standing dead trees) as well as several houses where they were roosting under the trim boards near the peak of the roof. We were able to mist net at two of the houses and captured 6 additional lactating females who were part of the same maternity colony. In all, these mother bats led us to 24 roost sites in the Lambert’s Cove Road area of Vineyard Haven. They moved their pups every few days until early July when most of the females stayed in one roost site at a house. We suspect this was because the pups were older and too heavy to move any longer. Within several days, the evening emergence count numbers at the roost increased to where we were seeing many more bats emerge than 6 or 8 when it was just the females. This indicated pups were becoming volant, which was exciting to see. We had one of very few successful breeding colonies documented this summer in the Northeast for NLEB. In July, near the west end of Edgartown Great Pond, we captured a lactating female in oak woodlands who was sharing a roost tree with at least 3 other bats. In Oak Bluffs, near Major’s Cove, we captured a newly volant juvenile male at a roost site on a deck in mid-July.
We returned to these colonies in 2016 and found the Lambert’s Cove and Major’s Cove colonies were both active! Our most exciting moment of the summer was in July, when we found several bats roosting at the house that served as the final maternity roost in 2015 for the Lambert’s Cove colony. We set nets and captured 4 adult females. One of the females was a female we had banded the prior summer. She had survived the winter! Because we captured the females later in the summer than in 2015, we were able to document several new roost trees for this colony that the females used once pups were volant (flying). At the Major’s Cove colony, we captured 4 adult females and 4 volant male pups in July. We located 2 other house roosts and were able to document where these bats were foraging at night before they dropped their nanotags.
The life history information we gather on NLEB will assist the U.S. Fish and Wildlife Service in developing recovery and management recommendations where NLEB still exist in the Northeast. It will also inform land management decisions on the Vineyard to protect maternity roosts for these bats. BOEM will be using any data gathered on offshore movements of bats tagged on the Vineyard to assess potential impacts of offshore wind development in this area on NLEB and other bats.
Winter 2015 Priorities
We tracked two female bats this fall to several roost sites, but not to any roosts where either could spend the winter. We believe NLEB are hibernating on Martha’s Vineyard because neither of these females left the Island during the swarming and mating season (September/early October). We are investigating possible hibernacula sites and look forward to hearing from people around the island who may have information about possible winter hibernacula sites for bats.