Why Nesting Earlier May Not Be Enough for Northern Tree Swallows in a Warming World

  • Three young Tree Swallows peek out of a wooden nest box entrance. They look ready to fledge.
    Why Nesting Earlier May Not Be Enough for Northern Tree Swallows in a Warming World

    A new study of nearly 95,000 Tree Swallow nests from across North America found that these birds are laying eggs earlier as springs get warmer. Even though Tree Swallows are adjusting their nesting timing in response to climate change, northern populations have been declining while southern populations have remained stable or even increased. The findings suggest that birds in the north may have a harder time keeping up with rapid warming and other challenges, making them more vulnerable to population declines.

  • Four images clockwise from upper left: A monitor holding a pole up next to a wide telephone pole where the tops of the poles are out of frame; A field technician in a forest holding a small bird in her hands; a green and white hummingbird sitting in a nest that is covered in lichen and built on a tree branch; and five feathered chickadee nestlings with their eyes open in a mossy nest that was built inside a wooden nest box.
    eNews June/July 2026

    – How to Make a Nest-checking Pole for Tall Nests
    – New Small Grant Program
    – Bulk Upload Win
    – New Chapters

  • A woman holding a tall rigid pole angled up into the entrance hole of a large nest box that has been mounted on a thick power pole, high out of reach.
    Monitoring hard-to-reach nest boxes? Try a camera pole!

    Do you have nest boxes that are mounted too high to easily inspect without a ladder? In this month’s blog post, we outline some easy steps to make a DIY nest-checking pole which eliminates the need for a ladder during nest inspections. Lightweight, inexpensive, and easy-to-use, this DIY tool can be operated by one person.   

  • Clockwise from upper left: Two kestrels perched atop a wooden nest box; Three blue eggs in a nest made from twigs of varying sizes. The nest has plastic interwoven into the nest cup; An adult flycatcher with food in its beak perched at the entrance of a wooden nest box ; and a darkened screenshot of the NestWatch website with a large video
    eNews May 2026

    – New Study Explores American Kestrel Decline
    – Reminder to Document Plastics in Nests
    – Watch: An Overview of NestWatch
    – New NestWatch Chapters

  • An adult kestrel perched at the entrance of a wooden nest box with a lizard, about to feed its chicks.
    Why Are American Kestrels Declining? New Insights from a Continental Study

    American Kestrels have been experiencing a long-term decline in populations. NestWatch data contributed to a recent study that brought together multiple data sources from around the continent. This integration of demographic data sources revealed new insights into how we can help reverse these declines.

  • Three blue eggs in a nest made from twigs and small branches. There is plastic incorporated into the nesting materials.
    Join Our New Study on Plastics in Bird Nests

    We’re noticing more birds weaving bits of human-made materials—like plastic bags or fishing line—into their nests, and we’re curious about what that means for their success. Could plastic pose risks, or might it offer some unexpected benefits? This summer, we’re teaming up with a Cornell University student to find out, and we’d love your help. If you find and monitor an American Robin, Gray Catbird, or Northern Mockingbird nest, you can snap a couple of quick photos (from the side and above) and upload them to NestWatch. By comparing nests with and without plastic, we can learn more about how these materials affect birds.

  • An alligator and a Snowy Egret enjoying a swampy area.
    Protective Nesting Associations: the predator next door

    Sometimes building a nest near predators can be a good thing! Let’s explore the different ways some birds take advantage of nesting near to animals that are a few steps higher up on the food chain—in other words, their predators’ predator.

  • Four images, clockwise from upper left: A Red-eyed Vireo feeding its nest of young amount bright green leaves, with the text 'the hidden world of nests and eggs' overlaid on top of the image; a eurasian bittern chick sitting on the ground between two large white eggs in the reeds of a marshy area; an american kestrel perched at the entrance of a wooden nest box; four white eggs sitting in a grassy nest that's lined with several downy feathers.
    eNews March 2026

    – The Hidden World of Nests and Eggs
    – Join Us for Nest Trivia
    – New NestWatch Chapter
    – Data Win

  • Four images, clockwise from upper left: A grid of photos of bluebirds with insects in their beaks; a close-up view of the face of a fox-like mammal with pale gray fur and large dark eyes; a small yellow songbird perched on a wooden nest box, singing its heart out; and a wren perched on the roof of a nest box with a large spider in its beak.
    eNews February 2026

    – Hungry Hungry Bluebirds
    – A Mystery Mammal
    – New NestWatch Chapters
    – Data Win