Finding a dead bird in your yard can be surprising. This article explores factors contributing to bird mortality in residential areas, including natural causes, human-influenced elements, and disease.
Natural and Environmental Explanations
Birds experience a natural life cycle, and older birds may succumb to old age, especially during challenging environmental conditions. Starvation can also be a factor, particularly for young birds or during harsh seasons when food sources become scarce or inaccessible.
Predation by wild animals is another common cause of bird deaths. Raptors such as hawks and owls, as well as terrestrial predators like snakes, foxes, and raccoons, naturally hunt birds for sustenance. Extreme weather events, including severe cold snaps, intense heatwaves, or heavy storms, can overwhelm birds, leading to exhaustion, exposure, or an inability to find shelter and food.
Human-Caused Factors
Many instances of bird mortality in residential areas are linked, directly or indirectly, to human activities and infrastructure. Collisions with windows are a very frequent cause of death for backyard birds, as they may not perceive glass as a barrier and attempt to fly through reflections. Vehicle strikes also account for numerous bird fatalities, particularly near roads and in areas with high traffic volume.
Accidental poisoning from pesticides, herbicides, or rodenticides used in yards can severely harm or kill birds that ingest contaminated prey or feed on treated plants. Domestic cats, both outdoor pets and feral populations, are significant predators of birds. These human-related factors are often preventable.
Disease and Contaminants
Avian diseases can cause bird deaths in residential settings. West Nile Virus (WNV), caused by a flavivirus, is transmitted to birds through infected mosquitoes. While many infected birds survive, some species, like crows and jays, can die from the infection, showing neurological symptoms. There is no evidence that people can get WNV directly from handling infected birds.
Avian Influenza (AI), commonly known as bird flu, is caused by influenza A viruses and can spread among wild aquatic birds and poultry. Highly pathogenic strains cause severe illness and high mortality, with symptoms including sudden death, respiratory distress, or neurological signs.
Salmonellosis, a bacterial infection, is common in songbirds, especially in winter, and spreads through contaminated bird feeders. Infected birds may exhibit ruffled feathers, diarrhea, and lethargy.
Environmental contaminants also pose a risk. Lead poisoning in birds often results from ingesting discarded fishing weights, lead shot, or fragments from ammunition. Birds can become emaciated and die within two to four weeks of ingesting lead, displaying symptoms like incoordination, weakness, or green watery diarrhea.
What to Do When You Find a Dead Bird
When you discover a dead bird, take precautions to protect yourself and others. Never touch a dead bird with bare hands, as its carcass may carry pathogens. Instead, use disposable waterproof gloves or an inverted plastic bag to pick up the bird.
After picking up the bird, double-bag the carcass by placing it into a thick plastic bag and sealing it securely. Dispose of the double-bagged bird in a secure trash container inaccessible to children or animals. Thoroughly wash your hands with soap and water after disposal, even if you wore gloves.
If you find multiple dead birds or suspect disease, contact your local animal control, wildlife rehabilitation center, or public health department. These agencies can provide guidance on reporting and may collect the bird for testing, particularly for suspected avian influenza or West Nile Virus. Some states have specific hotlines for reporting dead birds.