The Brown Marmorated Stink Bug (BMSB) is an invasive insect first introduced to North America in the mid-1990s. This species is a pervasive pest, causing significant damage to various fruit, vegetable, and field crops, leading to substantial economic losses for agriculture. These shield-shaped insects also become a significant nuisance when they aggregate inside homes during the fall to seek shelter for the winter months. Homeowners and gardeners often wonder if birds consume stink bugs, as finding natural predators is a primary interest for biological control.
The Stink Bug Defense Mechanism
The reason many generalist predators, including most birds, avoid stink bugs lies in the insect’s sophisticated chemical defense system. When threatened, the stink bug releases a pungent odor from specialized glands located on the underside of its thorax and abdomen. This mechanism functions as a strong deterrent to potential attackers.
The characteristic “stink” and foul taste are primarily due to a cocktail of volatile organic compounds, specifically two aldehydes: trans-2-octenal and trans-2-decenal. These chemicals are highly unpalatable and act quickly to repel a predator that attempts to consume the bug. This effective anti-predator strategy is the main barrier preventing widespread avian predation.
Specific Bird Species That Eat Stink Bugs
Despite the chemical deterrents, some birds have been scientifically documented to consume the Brown Marmorated Stink Bug (BMSB). Researchers using molecular analysis on fecal samples confirmed that at least three common North American bird species prey on the BMSB:
- The Northern Cardinal (Cardinalis cardinalis)
- The Tufted Titmouse (Baeolophus bicolor)
- The Carolina Wren (Thryothorus ludovicianus)
While the incidence of consumption was low, it confirms that some native birds are adapting to this invasive food source. The Northern Cardinal and Tufted Titmouse are omnivores, consuming a varied diet of seeds, berries, and insects, which may allow them to tolerate the unpalatable meal. Anecdotal evidence also suggests that larger, ground-foraging birds, such as domesticated chickens, turkeys, and certain types of grackles, will consume stink bugs, likely due to a higher tolerance for the defensive chemicals.
Encouraging Birds as Natural Pest Control
Gardeners and homeowners can encourage insectivorous birds to frequent their property as a component of natural pest management. Creating a hospitable habitat is the most effective approach to attracting the species that may consume stink bugs. Providing safe, dense cover in the form of native trees and shrubs offers crucial nesting sites and protection from weather and predators.
An easily accessible, reliable source of fresh water is another strong attractant for birds, especially if the water is moving, such as in a bird bath with a bubbler. While many insect-eating birds prefer live prey, offering supplemental food like high-protein suet cakes or dried mealworms can keep these species in the area during times when insect populations are low.