Bird Surveys

Untangling White-eyed Vireo from net
A White-eyed Vireo being taken out of a mist net during a MAPS survey in 2020.

NPS Photo/ Nathaniel Leies

Bird surveying has been conducted in different ways many times since before the establishment of Mammoth Cave National Park in 1941. Bird surveys offer a way to learn not only about population trends; surveys can also indicate the overall health of an ecosystem, assist managers in understanding impacts of visitor access or other human caused disturbances, and help pinpoint vulnerable and endangered species which require special management.


History of Bird Surveys at Mammoth Cave

Individual surveys have been conducted during three differing time periods of park development:

  • during the Civilian Conservation Corps (CCC) era, in the 1930s, when the CCC men were planting trees across the farmlands
  • as the young forests were growing from the open fields from 1946 through the 1960s
  • around 2005 in areas with secondary forest of moderate maturity

Individual bird surveys continue to this day.

Bald Eagle
A bald eagle is spotted during a nest survey on May 4, 2021.

NPS Photo/ Brice Leech

Different Goals Need Different Surveys

Breeding Bird Survey

A Breeding Bird Survey by the United States Geological Survey (USGS) has been conducted in the park almost every year from 1966 to 2019. These surveys, coordinated through the USGS Patuxent Wildlife Research Center, have been conducted across North America since 1966 to monitor bird population trends. These data can inform researchers and wildlife managers of population changes, revealing where efforts can be focused to reverse declines before populations get decimated to the point of extinction.

Christmas Bird Count

Christmas Bird Counts have been conducted annually across North American since 1900, and at the park since 1948. This data, like the Breeding Bird Survey, help wildlife managers keep up with population trends of the birds across North America and can assist managers in trying to understand what is causing population declines.

The history of Christmas Bird Counts began in 1900, when birders began to see declines in bird populations. In that time period hunters often participated in a “Christmas Side Hunt”, a tradition where the hunter with the most birds at the end of the day won. Birders thought a Christmas bird census might be a better idea, they reinvented the tradition and thus began the Christmas Bird Count.

The event of a Christmas Bird Count has become the longest running Citizen Science survey in the world. Counts are conducted at national parks, state parks, and many other natural landscapes. Learn more about The Audubon Society, which coordinates this effort today, and find nearby opportunities to join a Christmas Bird Count.


Monitoring Avian Productivity and Survivorship

The Monitoring Avian Productivity and Survivorship (MAPS) bird survey is coordinated by the Institute for Bird Populations (IBP). IBP was founded in 1989 to try to understand the causes of declines in bird populations.

MAPS studies the songbirds and passerines during their breeding season by using mist nets to catch birds, and then researchers look at characteristics of each bird, collect age, sex and condition, and release the bird as quickly as possible. Most surveys collect bird counts by listening and watching, which is important to finding population trends. MAPS data works with the other surveys to get a better understanding of how population trends may be changing, what may be the cause of the declines, which can assist wildlife managers even further. MAPS has been running at the park since 2004.

A small blue bird being held in a hand

NPS Photo/ Brice Leech

What Have We Learned from Bird Surveys?

Prior to park establishment, the park lands were primarily farming communities with ponds spotting the landscape among the open farm fields. The bird species denoted this type of open field and forest edge habitat with several sparrow species: pie-eyed grebe, loggerhead shrike, barn owl, short-eared owl, roughed grouse, northern bobwhite, and the bobolink all found in a more open habitat.

Today Mammoth Cave National Park consists of approximately 53,000 acres of forested and riparian habitats and these sparrow species are not often found in the park. Some of the species of migratory warblers found nesting in the park today that were not found early on are the blue-winged warbler and the northern parula.

Bald eagles have also begun to increase across the state of Kentucky, and the park has become home to several pairs. Monitoring efforts by park staff have tried to keep up with the success and productivity of each nest.

Bird surveys of all types are important to understanding population trends and dynamics. Without people willing to get up before dawn to observe birds we would not see the trends across this country. Some estimates state that the population of birds in North America have been in decline as much as 29% since the 1970s. How will this kind of decline in bird populations affect us? Only the future will tell.


Last updated: March 31, 2023

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P.O. Box 7
Mammoth Cave, KY 42259-0007


270 758-2180

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