Thursday, August 27, 2020

Understanding declines of aerial insectivores in North America

 A growing body of research demonstrates that aerial insectivores as a group are undergoing population changes, and in some species (nightjars, some swallows) are experiencing population declines.

The following papers describe some of what has been learned:

Evidence for multiple drivers of aerial insectivore declines in North America

Kimberly J Spiller, Randy Dettmers.
The Condor, Volume 121, Issue 2, 1 May 2019

 "Aerial insectivores (birds that forage on aerial insects) have experienced significant population declines in North America. Numerous hypotheses have been proposed for these declines, but current evidence suggests multiple factors could be operating in combination during their annual migratory cycles between breeding and nonbreeding areas. Potential drivers include decreased prey abundance, direct or indirect impacts of environmental contaminants, habitat loss, phenological changes due to warming climate, and conditions on migratory stopover or wintering grounds."


 Nebel, S., A. Mills, J. D. McCracken, and P. D. Taylor. 2010. Declines of aerial insectivores in North America follow a geographic gradient. Avian Conservation and Ecology - Écologie et conservation des oiseaux 5(2): 1. [online] URL:

Kevin C Fraser Bridget J M StutchburyCassandra SilverioPatrick M KramerJohn BarrowDavid NewsteadNanette MickleBruce F CousensJ Charlene LeeDanielle M MorrisonTim ShaheenPaul MammengaKelly ApplegateJohn Tautin.  2012. Continent-wide tracking to determine migratory connectivity and tropical habitat associations of a declining aerial insectivore. Proceedings. Royal Soc. B.2794901–4906

Thursday, July 2, 2020

Western Meadowlark: an iconic grassland bird in decline

Grasslands are among the most threatened habitats in North America. Loss of or alteration of this habitat to many other land-uses has had harmful effects on grassland birds, mammals, and other wildlife species that are found here. The study referenced below has shown that grasslands have lost more than 700 million birds in the last half-century - a total decline of more than 40 percent.

The Western Meadowlark is still found in grasslands in the United States, Mexico and Canada. These distinctive and colorful birds are melodic singers. In their habitat, they nest on the ground, and feed themselves and their young on insects and seeds.This meadowlark species is still relatively common, but recent trends exhibit population declines.

Learn more about this iconic grassland bird:

This graph shows the trend for the population across its US range:

Tuesday, April 7, 2020

Chimney Swifts: get ready for their return!

In Wisconsin, we have an excellent group focused on conservation of the Chimney Swift: the WI Chimney Swift Working Group:

Please check out their website to learn more about swifts, their ecology, how to become more involved, and how to participate in "Swift Nights Out" this year. All of those activities are important for protection of this species.

Friday, March 6, 2020

Bank Swallow news

Bank Swallow, Ph. by Manoj Karingamadathil  - Wikim. Commons

Of all of the aerial insectivores in our broad geographic area, Bank Swallow is the one that is being lost the most rapidly.

Learn more:
Partners in Flight species assessment

Canada species assessment

Manitoba Species At Risk

Reproductive success and health of breeding Bank Swallows (Riparia riparia) in aggregate (sand and gravel) pit and natural lakeshore habitats

North American Bank Swallow numbers declined by 94% from 1966 to 2014

Wednesday, February 5, 2020

parallel declines in abundance of insects and insectivorous birds

Parallel declines in abundance of insects and insectivorous birds in Denmark over 22 years

Anders Pape Møller

See the paper at this link:

 Dr. Anders Pape Moller completed a 21-year study that demonstrates how declining insect abundance may be linked to declines in numbers of insectivorous birds. Published last spring in the journal Ecology and Evolution...

 "This 21‐year study of insect abundance showed a tenfold decline. The decline in insect abundance reported here could partly be attributed to changes in climate. Such declines in insect abundance may have consequences for reproductive success in insectivorous birds such as hirundines (swallows), but also have consequences for population size as documented in the present study. Long‐term population declines in abundance of insects must have important consequences for insectivores, interspecific interactions, and ecosystem functioning."

Monday, January 6, 2020

using eBird; ways to improve your checklists

If you've been using eBird, good for you. If you haven't tried it, you really might want to start.

Here are a few reasons:

It's easy. It's fun.

It makes your data useful to science in a broad array of ways  - consider the recently-completed 5 years of field-work on the Wisconsin Breeding Bird Atlas II, which gathered data from

125,641 checklists, submitted by 2,147 participants

Here's a great set of ways to improve your checklists:

Thursday, December 26, 2019

learn about and join the Midwest Migration Network

About the Midwest Migration Network

The Midwest Migration Network (MMN) facilitates regionally-coordinated migration monitoring and research to address information gaps in the Midwest. Although focused primarily on landbirds, the Network welcomes anyone interested in advancing the study of the migratory ecology of birds and other animals in the Midwest. For the purposes of our Network, the Midwest region includes the states of Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio and Wisconsin (U.S. Fish & Wildlife Service Region 3).
Interested in joining the MMN? Learn more about membership.

Our Projects


The Midwest Migration Network focuses on three research initiatives: Banding & Ground Surveys, Radar Ornithology, and Telemetry. The goal of each initiative is to coordinate a regional understanding of migration through a shared research methodology designed to promote conservation of the Network's partner-generated Focal Species by answering its priority Research Questions.

Learn more at our website: