Dane County Humane Society’s (DCHS) Wildlife Center admitted a total of 14 unique warbler species between August 1st and October 15th, 2025 – this year’s primetime for migration when vast numbers of songbirds were documented moving towards Central and South America. While some warblers use Wisconsin for their breeding grounds during summer, most pass through the state for only a few weeks during the spring and fall months, stopping in one location or another to feed and rest before continuing their long journeys.
For these birds, completing a full migration cycle from North to South is crucial towards maintaining stable populations; where adults produce young, teach them how to survive in this world, and lead them by example. Yet, migration is exhausting and dangerous work, and over one million birds will crash into human constructs along the way. Most notable are residential windows that bait birds into flying fast and hard into the glass as they reflect nearby vegetation that birds think they can hide in or show a safe pass-through away from danger. Birds may die immediately on impact, or they become injured and suffer from common symptoms like concussions, skeletal fractures, central nervous system (CNS) damage, or generalized lethargy. In a matter of seconds, these birds are grounded, vulnerable to predation, and rarely able to fly away.
Wildlife rehabilitators play an important role in avian conservation efforts by mitigating some of the damages: providing medical treatment to affected birds, education and outreach to the public, and support to partner organizations that aim to reduce anthropogenic injury and mortality rates caused by window strikes to wildlife. For example, over 170 individual warblers were admitted to DCHS’s Wildlife Center for rehabilitation between January 2014 and October 2025, of which 71 percent were brought in because of known window strikes (or were strongly suspected based on their circumstances). Each warbler was provided with emergency veterinary triage, safe shelter, and temporary pain relief. While 35 percent of those birds died in transport, on arrival, or within 24-hours of hitting a window, 47 percent (almost half) of them were successfully released. Knowing this information helps inform the public about what rehabilitation is and how important this work is. It further ignites collaboration with institutions such as the Southern Wisconsin Bird Alliance, with whom DCHS began conducting window strike surveys, implementing window strike reduction displays, and holding workshops in 2025.
Tennessee Warblers (TEWAs) comprise almost 20 percent of total warbler admissions, followed by Golden-crowned Kinglets (GCKIs) sitting at 16 percent of admissions. However, both species experience drastically different life histories, with one being a potential semi-partial migrant in Wisconsin (GCKI) and the other being a long-distant migrant through Wisconsin to South America (TEWA):
Regardless of where birds come from or where they are going, rehabilitators must be prepared to work with any number of avian species if they are admitted sick or injured – not only from the medical side, but from the ecological perspective, too. Each kind of warbler has a specialized diet, habitat preference, and conditioning requirement that coincides with the time of year. Using these two warblers as an example, Golden-crowned Kinglets prefer lower-height shrubby vegetation with lots of available insects to eat, like spiders. They act much like chickadees do while hanging upside down and gleaning bugs off leaves and branches. Tennessee Warblers are larger warblers, weighing 3 to 4 grams more than a kinglet, that like to be up high-up in the tree canopy eating caterpillars or budworms.
Both need extensive flight time and exercise after initial treatment so that they can maintain endurance for migration. Moreover, as social birds, they should be ideally released in mixed flocks that contain their same species to fly home with. If migration is missed due to the nature or timing of recovery, holding them in rehabilitation until the next migration period may be key to their survival – especially if the species is sensitive to temperature fluctuations or needs to sustain themselves on a specific food type that has seasonal availability.
Successful songbird rehabilitation comes from a combination of knowing how to provide proper medical care, housing, and nutrition to each species, knowing whether they migrate through their region (and when), and giving individuals the best care possible in the shortest amount of time until they can be released. Warblers are a special group of birds, full of beauty and diversity, worth saving – every single one.
– Jackie Edmunds is the Wildlife Program Manager at DCHS's Wildlife Center
Photo at top of story: Blackpoll Warbler, #25-2765, was admitted on September 25th after suffering a scapula fracture from a window strike. It was released on October 12th after a full recovery.
