There are a few potential reasons why a mother bird may abandon her nest before her eggs hatch or her chicks fledge. Understanding the cause can help people provide support when needed or avoid disturbing nests unnecessarily. Some of the most common reasons for abandonment include:
Disturbance
One of the top reasons mother birds abandon their nest is disturbance. Birds can be very sensitive to noise, movement, and human activities near their nesting site. Excessive disturbance stresses the parents and may cause them to leave the eggs or chicks behind to find a quieter, safer location elsewhere. Sources of disturbance include:
- Loud noises like construction, traffic, barking dogs
- Vibrations from vehicles or heavy machinery
- Frequent human presence near the nest
- Predators like cats, crows, jays hanging around
If the disturbances are temporary, the parents may return. But ongoing commotion often leads to full abandonment. People should avoid disturbing active nests whenever possible.
Predation
Predators can cause abandonment in a couple ways. Adult birds may flee the nest when a predator attacks them directly. And some species will desert the eggs or chicks if they sense a predator has discovered the nest location. They essentially cut their losses and try again elsewhere.
Common nest predators include raccoons, snakes, cats, crows, jays, and hawks. Areas with an abundance of these predators see higher rates of abandonment. Removing predator access can help avoid this issue.
Insufficient Food
Raising young is energetically expensive for parent birds. They need to work tirelessly to gather enough food day after day. If resources are scarce near the nest, the effort may become impossible.
In these cases, the parents may abandon the nest to save their own health and survival. They instinctively understand they cannot adequately provide for the chicks.
Habitat loss, drought, contact pesticides, and climate change can all reduce food availability around a nest. Providing supplemental food like seed or suet cakes could potentially help parents cope.
Harsh Weather
Extreme weather like cold snaps, heat waves, flooding, or drought can also cause abandonment issues. The parents may struggle to maintain the necessary nesting conditions or find food in these circumstances.
If the difficult weather lasts more than a few days, abandonment becomes likely. And extreme one-off events like hailstorms, tornadoes, or hurricanes may instantly force parents to flee.
Providing shelter from the elements or supplemental food/water sources can assist birds during harsh weather nesting attempts.
Illness or Parasites
Sick parent birds often must abandon their brood. Their weakened state leaves them unable to properly care for or defend the nest.
Common bird illnesses include avian influenza, salmonella, trichomonosis, aspergillosis, and avian pox. Parasites like mites, lice, and mosquitoes can also compromise nesting efforts.
Treating underlying health issues or preventing parasites may help sick birds stay with the nest. If they must abandon, rescue organizations may be able to intervene and incubate eggs or raise chicks.
Inexperience
First-time nesters occasionally run into issues like improper nest placement, inefficient brooding, poor feeding, or ineffective defense against threats. These problems may force them to bail out on the nesting attempt.
But if they can gain experience and return to try again next year, their odds often improve. Fledging young is a learning process for birds. Supporting inexperienced birds as best we can is important.
Infertile Eggs
If none of the eggs in a clutch are fertilized and developing, the parents will abandon that nesting attempt. Without the prospect of offspring, they lose investment in those eggs.
Infertility happens occasionally, but unusually high rates may signal an environmental issue affecting bird health and reproduction. Habitat quality, chemical contamination, and disease outbreaks are examples factors that could influence fertility.
Dead Mate
If one parent dies during the nesting season, the other often abandons the nest. Raising a brood alone requires more work than a single bird can handle.
Exceptions are waterfowl like ducks and geese where the male rarely assists with rearing young. But in most species, losing one parent early dooms the nesting attempt. Predation, collisions, disease, and human activities take adult bird lives yearly.
When to Intervene
Finding an abandoned nest can be heartbreaking if the eggs or chicks are still alive. Our impulse may be to intervene and rescue them. However, good intentions can sometimes do more harm than good in these cases.
As a rule, abandoned eggs are nearly always non-viable. Without the parents continually incubating them, the embryos will die within a day or two. Bringing the eggs inside rarely results in successful hatching.
Abandoned chicks have better prospects, but still require expert care around the clock to survive. Improper food, hydration, brooding temperature, and handling can all be lethal. Often the kindest option is to leave chicks in the nest in case parents return.
Only licensed wildlife rehabilitators have the training and resources to properly rescue and raise abandoned young. It’s best to contact them for guidance rather than intervening ourselves unless the animal is in immediate mortal danger.
Here are good rules of thumb for when to call for assistance:
Situation | Recommendation |
---|---|
Healthy chicks in nest | Leave alone for possible parent return |
Injured/weak/dehydrated chicks in nest | Contact rehabber immediately |
Chicks on ground unprotected | Contact rehabber immediately |
Eggs unattended more than 24 hours | Eggs likely non-viable; remove nest |
Live chicks fully feathered in or near nest | Fledglings likely okay; monitor from afar |
With the guidance above, you can ensure abandoned babies get the best chance while avoiding risky interference. Let trained experts handle tricky rescues.
Preventing Abandonment
In some cases we can take proactive steps to help parent birds continue nesting rather than abandoning:
- Avoid disturbing active nests and baby birds. Watch from a distance.
- Don’t let kids or pets harass nesting birds.
- Limit noise, motor vehicles, and excessive activity near nest sites.
- Provide shelter from severe weather and predators.
- Supplement food and clean water if resources are scarce.
- Control nest-raiding predators like raccoons, cats, and rats.
- Eliminate pesticide use which reduces insect food sources.
- Properly manage dead trees, fallen branches, and other nesting sites birds rely on.
With some planning and wildlife-friendly practices, we can give parent birds the best chance of success. Healthy habitats and minimizing disturbances are always key.
Dealing with Remains
When eggs or chicks in a nest have died, proper handling of the remains is important. First, check if the parents are still returning to the nest. If so, do not interfere or remove the bodies yet. The parents may still be grieving the loss.
If the nest is fully abandoned, wearing gloves to remove and dispose of the bodies is safest. Placing them in a sealed bag in the trash is appropriate. Never touch dead birds with bare hands due to risks of bacteria, viruses, and parasites.
Clean the nesting area by removing the nesting material and droppings and spraying with a 10% bleach solution. This helps prevent disease and avoids attracting predators to the scent. The parents may return to try nesting again in the future.
Understanding Grieving Birds
Parent birds exhibit recognizable signs of grief when they lose eggs or chicks. They may linger around the abandoned nest, call frantically, circle the area, or even carry away the dead bodies. Some may dive bomb or attack intruders near the nest in their distressed state.
These behaviors reflect mourning processes similar to those of intelligent mammals like elephants or whales. Birds appear to feel deep attachment to their lost offspring. Their grief may last days or weeks before they move on to attempt a new nest elsewhere.
Supporting grieving birds requires respecting their space and emotions. Minimalize disruptions near abandoned nests. Don’t remove eggs or dead chicks until parents have stopped returning for 1-2 days. Allow them the critical time they need to process their loss.
Summary
Bird parents abandoning a nest is always hard to witness, but often a normal part of their reproductive process. By providing supportive conditions, minimizing disturbances, and properly handling abandoned eggs or chicks, we can limit cases of abandonment and support parent birds when it does occur. Have compassion for grieving bird parents, while also recognizing the incredible resilience they show in moving forward after loss. Their dedication to eventually raising and fledging young in the face of obstacles serves as an inspiration.