Attracting insectivorous birds is a strategic method for managing flying insect populations, including mosquitoes, through natural biological control. Property owners can encourage their presence by creating a habitat that caters to the specific nesting, feeding, and safety requirements of these aerial hunters. This approach integrates avian life into the landscape, establishing a thriving micro-ecosystem where birds can successfully nest and raise their young, ensuring a consistent population of natural pest controllers.
Identifying Avian Mosquito Predators
While it is a common belief that certain birds specialize in mosquito consumption, studies show mosquitoes are often a minimal part of their overall diet, typically less than two percent for some species. Birds are opportunistic feeders that primarily target larger, more calorie-rich insects like dragonflies, beetles, and moths. However, the sheer volume of insects consumed by aerial insectivores means their presence still offers significant local control over the flying pest population.
Primary targets for attraction include the Purple Martin, North America’s largest swallow, and the abundant Tree and Barn Swallows. Flycatchers, such as the Eastern Phoebe, also contribute by snatching insects from the air and foliage. Nocturnal hunters like the Common Nighthawk feed at dusk and dawn when mosquito activity is highest, making them valuable contributors to a natural pest management system.
Providing Essential Shelter and Nesting Sites
Different species of aerial insectivores require distinct types of shelter, and providing a variety is the best approach for attracting a diverse group. Purple Martins are colonial cavity nesters, requiring multi-compartment houses mounted on poles 12 to 20 feet high. These houses must be placed in open areas at least 40 feet from trees or buildings. Tree Swallows, being solitary cavity nesters, will readily use single nest boxes installed on poles about five feet above the ground, featuring a 1.5-inch diameter entrance hole. Both swallow species benefit from the presence of dried grasses, twigs, and feathers, which they use to construct their nests.
Barn Swallows and Eastern Phoebes prefer open-front structures under protective overhangs, often utilizing man-made structures like sheds or eaves. Barn Swallows construct their characteristic mud nests on small wooden platforms mounted directly to a vertical surface. Ensuring a nearby source of wet mud is available is beneficial, as they use mud pellets to build their nests. Eastern Phoebes utilize open-sided nesting platforms, typically eight inches square, placed beneath the roof of a porch or eave.
Optimizing Food and Water Resources
While the main food source is the flying insect population, supplemental resources can support nesting pairs, especially during periods of low insect availability. Purple Martins do not use seed feeders but benefit from crushed, baked eggshells, which provide a calcium supplement for nesting females. Flycatchers and swallows can be supported by offering dried insect protein like mealworms or high-calcium Calci Worms, placed in shallow, open dishes during the breeding season.
Providing a reliable water source is equally important, but it must be managed carefully to prevent it from becoming a mosquito breeding site. Bird baths should be shallow, ideally no more than two inches deep, with a gradually sloped edge to allow small birds safe access. The key to mosquito prevention is water movement, which disrupts the female mosquito’s ability to lay eggs. This motion can be achieved by installing a small solar-powered fountain, a water agitator, or a simple DIY drip system. Non-toxic mosquito dunks containing the larvicide Bacillus thuringiensis israelensis (Bti) can also be used, as this is harmless to birds, pets, and humans.
Maintaining a Safe, Chemical-Free Environment
Protecting the attracted insectivores from hazards ensures their continued success in the area. The use of chemical mosquito fogging, broad-spectrum insecticides, and lawn pesticides must be eliminated, as these poison the birds’ primary food source and can harm the birds themselves. A thriving insect population is necessary to sustain a healthy bird colony, particularly when parents are foraging to feed their nestlings.
Predator mitigation is a necessary step for any artificial nesting setup. Pole-mounted houses for martins and swallows should be equipped with a conical or stovepipe baffle, a metal barrier installed a few feet below the nest box to deter climbing predators like raccoons and snakes. For phoebe platforms or barn swallow nests under eaves, removing nearby vertical climbing hazards like wires or pipes can reduce access for arboreal predators. Making large windows visible with decals or hanging paracord strands will prevent fatal window strikes, which are a common threat to fast-flying birds.