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

Blackbirds live fairly short lives with a life expectancy of only 3 years. Many blackbirds do not live past their first year because of the environment. In captivity, blackbirds are known to live up to 20 years.
Blackbirds have such a high population because of their ability to find food in almost any habitat, making it able to live in a diverse setting. Blackbirds are even known to survive in harsh winters where other birds will starve.

Life Span

The Brewer’s blackbird, the red-winged blackbird, and the Yellow-headed blackbird are all native to North America and are considered the most abundant bird species in America.
In the US, the Migratory Bird Treaty Act of 1918, blackbirds are protected. However, under this act, blackbirds 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 blackbirds.

Population

Red-winged blackbirds nest in hayfields, marshes, and ditches while larger flocks can feel in fields and bottomlands.
Redwings will migrate to the southern portion of the US during the winter. Yellow-headed blackbirds nest in agricultural fields, meadows, and pastures and will migrate farther south into Mexico. Brewer’s blackbirds will nest in a variety of habitats and will migrate to the central and southern plains states.
Females of all breeds of blackbirds will born the nests, typically in areas in low shrubs and trees. Nests are formed using plant stems, twigs, grasses, and hair or other softer materials. These nests are formed into a cup and are sometimes comprised of mud and manure to cement the shape.

Nesting Habits

Feed per day: .04lbs per bird

Blackbirds will typically feed on the ground with their primary food being insects during nesting season and grain and weeds in the summer and winter months. During feeding, the males and females will split off into separated flocks, with females eating more insects than males do.
Blackbirds are known to cause considerable damage to ripening corn, sunflower, sorghum, oats, and sprouting and ripening rice. This can be very costly for farm and feed lots.

Feeding Habits

Female blackbirds will lay 3-5 eggs that will then hatch after 13-14 days. Young chicks will then leave the nest after 13-14 days after they have hatched. If the nest is disturbed, young chicks can leave and survive as early as 9 days after hatching.
Male birds will help young fledged birds while the female blackbirds will prepare for the next nesting. There is typically only a 30-40% chance that nesting will produce fledged young within this species of bird.