A widespread concern suggests that touching a bird egg will lead to its abandonment by the parent bird. This belief often causes well-meaning individuals to hesitate when encountering a nest or young bird. This article clarifies the science behind avian behavior and nest abandonment, offering guidance on responsible actions when finding a bird’s nest or egg.
The Truth About Human Scent
The common belief that birds will abandon their nests or young due to human scent is largely a myth. Most bird species possess a limited sense of smell compared to humans and other mammals. While birds can detect odors, their primary senses for identifying nests and offspring are sight and sound. Scientific studies and monitoring programs, where researchers regularly handle eggs and nestlings, demonstrate that parent birds continue to care for their young without issue.
Some bird species, such as kiwis, turkey vultures, and certain seabirds, have a more developed sense of smell for foraging or navigation. However, even for these species, there is no evidence that human scent alone on an egg or chick prompts abandonment. Birds are driven by strong parental instincts and a significant investment in their offspring, making them unlikely to desert their nests simply because of a human touch.
Common Reasons for Nest Abandonment
While human scent rarely causes abandonment, birds abandon nests for various reasons. Predation is a factor; if a nest is disturbed by predators, or if eggs or young are taken, parents may abandon the remaining clutch. Severe weather conditions, such as prolonged heavy rains or strong winds, can destroy nests or make them unsuitable for raising young, leading parents to leave.
Repeated disturbances, including frequent human presence, can cause parents to desert a nest if they perceive a constant threat. Infertility of eggs or the death of one or both parent birds can also result in abandonment. Parents might also leave a nest if eggs are nonviable or the site is unsafe.
Responsible Actions When Finding a Nest or Egg
When encountering a bird’s nest or a fallen egg, minimize interference. Observe from a distance to avoid causing stress to the parent birds. If you find a featherless nestling that has fallen, gently place it back if the nest is accessible. Most birds will not reject their young due to human handling.
If the nest is not accessible, or if you find a clearly injured bird, contacting a local wildlife rehabilitator is recommended. Fledglings, young birds with feathers that have left the nest but cannot yet fly well, should be left alone. Their parents are nearby, continuing to feed and care for them as they learn to fly.
Legal Protections for Birds
Many bird species, their nests, and eggs are protected by federal and state laws. In the United States, the Migratory Bird Treaty Act (MBTA) of 1918 makes it illegal to disturb, destroy, or possess migratory birds, their nests, or eggs without a permit. This law protects nearly 1,100 species, including most native birds commonly found around homes.
This protection reinforces the importance of not interfering with bird nests. Moving or removing an active nest, even if it seems to be in an inconvenient location, is prohibited without specific authorization. The MBTA aims to conserve bird populations by preventing unauthorized disturbance, emphasizing leaving nests and eggs undisturbed.