Biodiversity Research Institute
Biodiversity Research Institute
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Mammal Program
Mammal Program

Following BRI's initial mercury studies on mink and river otters, the mammal program quickly expanded to incorporate studies of other aquatic dwelling animals and bats.

There are more than 1,400 known species of bats, comprising nearly a quarter of all mammal species. These unique creatures are at the center of some of today's most pressing ecological issues, such as white-nose syndrome, a deadly fungus, and mortality associated with wind turbines. BRI biologists, collaborating across several programs, are conducting studies to address these issues.

Program Director:
Dave Yates

Why Study these Mammals?

Mammals have evolved to exploit a large variety of ecological niches and life history strategies. Each species attains a state of harmony with its environment through gradual adaptations, modifications and evolution, and must adapt to continual changes. Humans have become capable of making profound and rapid alterations in the environment; the future survival of most species is becoming more and more dependent upon our actions.

BRI focuses its research efforts on meeting the conservation needs of some species of mammals, and using them as bioindicators to evaluate the health of individuals, populations, and ecosystems. Below, we have grouped our primary areas of research emphasis into three nonexclusive areas: (1) contaminants monitoring; (2) movement studies; and (3) surveys and population monitoring.

Contaminants Monitoring

Contaminants Monitoring

In the U.S., more than half of the bat species forage adjacent to waterways. Bats are also long-lived (up to 30 years for some) and have the potential to accumulate high levels of toxins over time.

Below is a selection of some representative mammal contaminants research projects:

  • Evaluating spatial and temporal patterns of mercury exposure in northeast U.S. bat populations
  • Evaluating spatial and temporal patterns of mercury exposure in northeast U.S. mink and otter populations
  • Developing mercury lowest adverse effect levels (LOAEL) for U.S. bat populations
  • Penobscot River mercury study: mercury assessment in bats along the Penobscot River and comparison regions in Maine
  • Assessing bat, furbearer, and small mammal Hg profiles for Natural Resource Damage Assessments (NRDA) with USFWS, EPA, and various state agencies 
  • Examining bat mercury trends at Great Dismal Swamp National Wildlife Refuge, Virginia 
  • Penobscot River mercury study: mercury assessment in harbor and gray seals along the Penobscot River and comparison regions in Maine and Massachusetts
  • Peru mercury study examining mercury for gold mining using Giant River and Neotropical River otters as indicator species



Movement Studies: Banding

Movement Studies: Banding

Efforts to study the movements of mammals help us learn critical information about their behavior and ecology. Marking bats with unique wing bands is one of the most long-standing methods of studying bats. Traditional bands help us identify the banding origin of bats that are recovered or recaptured elsewhere.

Movement Studies: Tracking

Movement Studies: Tracking

Bats fitted with traditional radio transmitters are typically tracked within a relatively close range (several miles) by plane, vehicle, or on foot using a receiver. To date, BRI researchers have tracked a variety of bats including little brown, northern long-eared, Indiana, tri-color, big brown, gray, and eastern small-footed bats. Tracking these individual bats provides remarkable information that is valuable in a wide spectrum of research, management, conservation, and legislative decisions.

Below is a selection of some representative mammal tracking projects:

  • Home range study of little brown and tri-color bats on a river in Virginia
  • Home range study of northern long-eared and eastern small-footed bats at Great Bay National Wildlife Refuge
  • Examining muskrat movements and populations on a fluctuating reservoir in Downeast Maine
  • Home range movements of otter, mink, beaver, and muskrat on a fluctuating reservoir in western Maine
  • Tracking Indiana bats to day roosts and performing exit counts
  • Tracking eastern small-footed bats to rock roosts at Acadia National Park
  • Identifying Late Summer Activities and Habitat Preferences of Remnant Populations of Myotis Bats in Acadia National Park
Surveys and Population Monitoring

Surveys and Population Monitoring

Habitat loss and fragmentation cause a variety of ecological impacts that trigger different responses in different mammal species. Conducting surveys or monitoring populations shows trends in species populations. Depending on the objective of the study, we use a variety of methods to survey and inventory a species. These inventories are important to understand how the mammals we study utilize the landscape we share with them.

Below is a selection of some representative mammal survey and monitoring research projects:

  • Bat survey of Parker River and Great Bay National Wildlife Refuges 
  • Understanding bat migration in coastal Massachusetts (working with Parker River and Great Bay National Wildlife Refuges)
  • Ecoregion survey to determine rare bat and small mammal species in Maine
  • Characterizing bird and bat migration in the Thousand Islands region of New York State (with the U.S. Fish and Wildlife Service).
  • Gas pipeline surveys for endangered Indiana bats in Pennsylvania, West Virginia, and Ohio
  • Rare mammal inventory along the Appalachian Trail in Maine for the National Park Service
  • Acoustic monitoring of bats at various National Parks, National Wildlife Refuges, and various states for inventory purposes
  • Community structure of bats at Acadia National Park
  • Museum query for historical coastal bat occurences

Program Director
Dave Yates
207-839-7600 x114

Program Staff
Caroline Byrne

Contributing BRI Staff 
Dustin Meattey

Photo Credits: Header photo © BRI-Tim Divoll. Study subjects: Northern long-eared bat © Bat Conservation International; Eastern small-footed bat © BRI-Jonathan Fiely; Indiana bat © BRI-Jonathan Fiely; River otter © iStock; Mink © BRI-Jonathan Fiely; Harbor seal © Sharon Fiedler. In the field © BRI; Banded bat © BRI-Jonathan Fiely; Tracking © BRI-Dave Yates; Otter family © BRI-Dave Yates; Bat cave © BRI.
Biodiversity Research Institute