Birds carry and transmit over 60 different types of diseases! Here are just a few that negatively affect humans, pets, and 
livestock:

Aspergillosis
Avian Inﬂuenza (H5N1)
Blastomycosis
Candidiasis
Capillariasis
Chlamydial
Chlamydiosis
Coccidiosis
Cryptococcosis
Dermatosis
Echinostoma revolutum
Encephalitis
Erysipeloid
Fowl Cholera
Fowl Typhoid
Haplorchis Pumilio
Histoplasmosis
Hypoderaeum conoideum
Infectious Coryza
Listerious
Meningitis
Mycotic Diseases
New Castle Disease
Parasitic Nematodes
Parasitic Trematodes
Paratyphoid
Pasteurellosis
Protozoal Diseases
Pullorum Disease
Salmonellosis
Sarcosporidiosis
Schistosomiasis
Spirochetosis
St. Louis Encephalitis
Streptococosis
Taxoplasmosis
Trichomoniasis
Tuberculosis
Ulcerative Enteritis
Vibriosis
Viral Diseases
West Nile Virus
Yersiniosis

Diseases

Cowbirds are known to live almost 16 years in the wild. This is attributed to their aggressive behavior, their adaptability, as well as their ability to socially interact with other pest birds in a flock.

Cowbirds will typically forage on the ground with a mixed flock of birds that include blackbirds, grackles, and starlings.

Because of their nesting habits and being separated from their parents and other members of the flock, they will live and co-exist with other species of birds.

Life Span

Brown-headed cowbirds are common across out of North America. In the US, the Migratory Bird Treaty Act of 1918, cowbirds are a protected species. However, under this act, cowbirds may be controlled without a federal permit when they are found, “committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock or wildlife, or when concentrated in such numbers and manner to constitute a health hazard or other nuisance.”

You will need to consider your local and state laws before you take any type of control measures against cowbirds.

Population

Cowbirds are very unique in their nesting habits in that they do not build nests of their own and is what is considered to be a “brood parasite.” Female cowbirds will lay her eggs in the nests of other bird species who will then raise the young cowbirds. It’s estimated that brown-headed cowbirds will lady their eggs in more than 220 species of birds!

There are some birds that recognize the cowbird egg in their nest but are too small to get the eggs out of their nests. In these cases, new nests are built over the old one to try to prevent cowbirds from coming back. There are other species of birds that will throw cowbird eggs out of their nests or puncture the shells. The majority of birds do not recognize cowbird eggs at all.

Nesting Habits

Feed per day: .03lbs per bird

Cowbirds are ground feeders in that they typically forage for food in open areas on the ground looking for insects like beetles and grasshoppers as well as seeds from grasses and weeds.

Cowbirds are known to damage ripening sorghum, sunflower, and millet. They will also eat livestock feed and are found gleaning waste grain and seed from dung.

Feeding Habits

The cowbird is a brood parasite. This means that they will lay their eggs in the nests of other bird species. A female cowbird will quietly scope out an available nest where the other bird species is actively laying eggs. Once she has found a site, she will sneak into the nest when the host is away, usually remove or damage eggs in the nest, and replace it with 1 or 2 of her own eggs.

The host birds will then raise the young cowbirds. The incubation period is typically shorter with cowbirds than any other songbird species, meaning that these young birds will hatch first and grow very large quickly. This makes it easy for them to demand all of the food from their foster parents and reduces the chances of brooding success for the other nesting birds.