Purple martins are insectivorous birds that are known for their appetite for mosquitoes. However, mosquitoes make up only part of the purple martin diet. Purple martins eat a diverse array of flying insects besides just mosquitoes.
Major Prey Items
The major prey items in the purple martin diet besides mosquitoes include:
- Dragonflies
- Damselflies
- Flies
- Midges
- Bees
- Wasps
- Ants
- Beetles
- Butterflies
- Moths
Purple martins are aerial insectivores, meaning they capture insects while in flight. Any winged insect is fair game as a food source. Mosquitoes, flies, midges, and other small soft-bodied flying insects make up the bulk of their diet.
Consumption of Mosquitoes
While mosquitoes are an important part of their diet, research shows that mosquitoes may make up only around 15% of overall purple martin food consumption. Culiseta melanura is one of the most common mosquito species consumed.
The proportion of mosquitoes in the diet varies based on location and availability. One study in Florida found that mosquitoes comprised 29% of the purple martin diet during wintering grounds. However, mosquitoes made up only 3% of prey items at one breeding colony in Arkansas.
Dragonflies
Dragonflies are a prime component of the purple martin diet. Large dragonflies provide a lot of valuable protein. Estimates suggest dragonflies may account for nearly 25% of a purple martin’s food intake.
Some of the most common dragonfly prey include:
- Eastern Pondhawk
- Blue Dasher
- Widow Skimmer
- Common Green Darner
Purple martins hunt dragonflies in open fields and wetlands.
Other Flies
After mosquitoes, other types of flies make up a substantial portion of the purple martin diet. Flies help provide fat and protein.
Some flies commonly eaten include:
- House flies
- Blow flies
- Flesh flies
- Stable flies
- Deer flies
- March flies
These flies are often plentiful near farms, stables, and areas with livestock.
Wasps and Bees
Bees and wasps provide nourishment for purple martins. They are especially targeted when feeding their young.
Some of the most common bees and wasps eaten include:
- Honey bees
- Bumble bees
- Cicada killer wasps
- Mud dauber wasps
- Paper wasps
- Yellowjackets
Purple martins rely on their speed and agility to prey on stinging insects. The birds can quickly swoop in, grab a wasp or bee, and eat it before being stung.
Beetles
Beetles make up a small but regular part of the purple martin diet. Tiger beetles, ladybugs, June bugs, and scarab beetles are common prey.
While not a preferred food source, beetles provide variety and nutrients to balance the diet. Martins opportunistically capture beetles when encountered.
Butterflies and Moths
Butterflies and moths are a supplemental prey item for purple martins. They provide nutrients and fat.
Some butterflies and moths frequently eaten include:
- Monarchs
- Skippers
- Swallowtails
- Cabbage moths
- Corn earworm moths
Martins catch these insects in mid-flight above fields and meadows.
Ants
Though not a primary component, ants are part of the purple martin diet. Ants provide protein from their bodies and carbohydrates from the honeydew they ingest.
Purple martins opportunistically feed on flying ant swarms when available. Some common ant species eaten include fire ants, Carpenter ants, and Harvester ants.
Other Prey
Purple martins occasionally supplement their diet with other insects when the main prey items are scarce. Other prey can include:
- Grasshoppers
- Crickets
- Cicadas
- Leafhoppers
- Aphids
- Termites
- Lacewings
- Caterpillars
This diverse mix of insects provides a balanced source of protein, fat, vitamins and minerals.
Hunting Strategies
Purple martins have several hunting strategies to capture different flying insect prey:
- Hawking – Catching insects from a perch
- Flycatching – Catching insects while flying
- Aerobatic maneuvers – Quick turns and dives
- Robbing swarms – Plucking insects from mating swarms
Their agile flight allows them to swiftly change direction when targeting prey. Purple martins often forage in groups, capturing thousands of insects each day.
Diet Changes
Purple martin diets can change throughout the year as insect availability fluctuates. Mosquitoes and dragonflies make up more of the diet in early summer. Wasps, bees, and beetles are more common in mid to late summer.
Migration and breeding times can also impact prey consumption. For example, purple martins rely more on winged ants and termites when feeding nestlings.
Foraging Habitats
Purple martins have diverse foraging habitats to take advantage of seasonal changes in insect abundance, including:
- Fields
- Forest edges
- Rivers and lakes
- Marshes and wetlands
- Suburban yards
- Pastures
Aerial insects tend to congregate around water sources, so martins frequently hawk for prey over ponds, streams, and other wet areas.
Impact on Insect Populations
Purple martins provide natural mosquito and insect control. A typical colony can consume thousands of flying insects each day.
Studies suggest the presence of martins can decrease mosquito populations around homes by up to 90%. They are champion mosquito eaters in early summer when the insects are abundant.
However, purple martins alone are not an effective long-term mosquito control method. Their diet is too generalized on many other insects besides just mosquitoes. But they are still a welcome backyard predator to naturally reduce mosquitoes and flies.
Comparison to Other Bird Species
Other aerial insectivore birds have diets similar to purple martins. Close relatives like swallows and swifts feed on the same prey items.
The diet of the tree swallow is nearly identical to the purple martin, relying on dragonflies, flies, bees, wasps, and beetles. Cliff and barn swallows also have very similar food habits.
Chimney swifts feed heavily on flying ants, wasps, and beetles. Nighthawks focus more on moths, beetles, flies, and ants.
While their diets overlap, these species each have slightly different preferences and foraging strategies. Together, they provide natural pest control services across North America.
Conclusion
Purple martins are voracious predators of insects, targeting mosquitoes, dragonflies, flies, bees, wasps, butterflies, moths, and more. While mosquitoes are part of their varied diet, they do not exclusively feed on them. Purple martins are aerial insectivores adapted to catch a wide array of insects on the wing.
Their diverse appetite allows them to take advantage of seasonal changes in insect abundance and provide natural mosquito and pest control.
