Purple martins are migratory birds recognized for their graceful flight and remarkable aerial maneuvers. Their diet consists entirely of insects captured in mid-air.
The Core Diet: What They Eat
Purple martins are obligate aerial insectivores, meaning their diet consists almost exclusively of insects caught while flying. They consume a wide variety of airborne insects, including dragonflies, damselflies, and various flies like house flies, horse flies, deer flies, crane flies, and mayflies.
Their diet also regularly features beetles, butterflies, moths, grasshoppers, and cicadas. While a common misconception suggests they consume large numbers of mosquitoes, these insects make up less than 2% of a purple martin’s diet. This is primarily because mosquitoes are most active at dusk and dawn, times when purple martins are generally not foraging.
Purple martins are opportunistic, eating whatever suitable flying insects they encounter. They also consume wasps and bees, which can constitute a notable portion of their diet. Additionally, they have been observed eating invasive fire ants.
Aerial Hunters: How They Feed
Purple martins acquire their food while in flight. They typically forage at altitudes ranging from 150 to 500 feet, sometimes even higher. Their flight is characterized by swift, agile movements, allowing them to snatch insects directly from the air.
The birds are constant feeders, often spending up to five hours daily searching for and catching insects. They rarely land on the ground to eat, though they may do so in unfavorable weather conditions to find insects near the surface. Purple martins are known for their speed and excellent eyesight, enabling them to spot insects from distances up to 100 feet away. When encountering prey, they can turn suddenly, accelerate, and flare their tails to trap the insect. This aerial hunting strategy is highly effective, allowing them to capture a diverse range of flying prey throughout daylight hours.
Nutritional Needs and Consumption
The active lifestyle of purple martins, including their long migratory journeys and breeding activities, demands substantial energy. Their insect-based diet supports these high energy requirements. An individual purple martin can consume up to 2000 insects daily.
During the breeding season, both parents gather food for their young. They return to the nest with tightly compressed balls of hundreds of small insects, which are then fed to the nestlings. This intensive feeding ensures the rapid growth and development of their offspring. Purple martins also obtain water while in flight, skimming the surface of open water sources like ponds or lakes to scoop up water with their lower bill. During periods of cold or inclement weather, when flying insects are scarce, their energy reserves can quickly deplete, making supplemental feeding with protein-rich items like crickets or mealworms important for their survival.