For many backyard birders, attracting nesting birds is a great accomplishment, but not every bird is welcome in every backyard. If some birds are not welcome in your yard or your bird houses, there are simple ways to safely and effectively discourage their nests.

Why You Might Not Want Nesting Birds Nearby

There are many reasons why nests aren't always welcome. Different birders have different opinions about nesting birds, but in some cases, nesting birds aren't desirable, such as:

• Invasive Species: Invasive birds usurp nesting areas from native species, and their prolific breeding can take over territories and force other birds away from essential resources. Birders who want to protect native birds and encourage them to nest nearby may need to discourage invasive nesters.
   
• Messy Nests: Raising baby birds is a messy business, and a nest nearby means an accumulation of debris including loose nesting material, feces, molted feathers, discarded food and other unwanted items. If birds are nesting in an area where that mess is problematic, it may be necessary to discourage that nest.
   
• Protective Parents: Nesting birds can be very protective of their chicks, and some species will attack any intruders, including humans who might just be walking past. If these aggressive birds are nesting in popular areas, such as on a porch or next to an active garden path, it may be easier to discourage their nests instead of dodge their talons.
   
• Unsafe Nests: Birds generally choose safe, protected nesting locations, but they don't always recognize potential threats. If a nest is being built in a dryer vent, gutter or chimney or within reach of dogs or curious children, discouraging the nest can help prevent potential tragedies after the young birds hatch.
   

• Bird Phobias: While most birders are genuinely fond of the birds they see, there are times when a birder might have a bird phobia and would prefer to see birds through binoculars from a distance rather than have them nesting nearby. In that case, it may be best to discourage nesting rather than suffer from psychological distress from an otherwise enjoyable hobby.

Easy Ways to Discourage Nests

No matter what the reason for discouraging nests, there are many ways to do so without harming the birds or lowering their chances of raising a healthy brood of chicks. Before taking any steps to stop a nest, however, birders must be aware that nesting birds are protected under the Migratory Bird Treaty Act. It is illegal to disturb nesting birds or do any damage to an active nest or eggs, but birders can discourage nesting attempts before eggs have been laid. Ideally, it is best to make an area unsuitable for nesting long before the birds show an interest in building a nest, and these techniques can help:

• Restricting Entrance Holes: When unwanted birds take over bird houses, changing the entrance hole size is an easy way to keep them out. This is especially effective when larger birds such as European starlings or house sparrows are taking over houses meant for wrens, bluebirds or swallows. A front plate or a small section of pipe to create a tunnel to the entrance are easy ways to fix bird house entrances so unwanted birds stay away.
   
• Block Cavity Entrances: Cavity-nesting birds may investigate a wide range of unsuitable nest sites, such as dryer vents, pipe fittings, chimneys or small holes that lead to attics or other places they are not welcome. Blocking those entrances with hardware mesh, wood scraps or other deterrents can keep the birds from nesting, but be sure there are no birds inside the cavity when the blockage is installed.
   
• Slope Ledges: Many birds build nests on convenient ledges, including under house eaves, on porches or on any somewhat level site, such as a porch lamp or clothesline post. Because these ledges are often part of a structure, it can be difficult to remove them, but sloping the ledge can make it impossible for birds to successfully nest. Add a block, board or other material to create a slope steeper than 45 degrees and birds will not be able to construct a nest.
   
• Spring Barriers: In areas where birds are nesting on ledges and it may be impossible to effectively create a slope to discourage the nest, line the area with a loose spring instead. The coils of the spring are not suitable to nesting, and a simple spring is easy to attach with hardware staples or clips. For the best results, choose a spring with at least an inch between each coil so the surface is suitably unstable.
   
• Light Flashes: Birds like quiet, undisturbed places for nesting, and random flashes of light can make the birds more nervous and less likely to build their nest in that location. Add several small mirrors to unwelcome nesting sites and birds may not only move on because of the light, but their own reflections could fool the birds that the site is already claimed. Mylar strips, reflective wind chimes and pieces of aluminum foil dangling in a small mobile are other options.
   
• Pruning: When birds are nesting in trees and bushes, pruning those plants can encourage the birds to move along because the space becomes more open and offers less shelter and concealment. Pruning away good nesting spots, such as sturdy crooks between limbs, can also help discourage unwanted nesting.
   
• Remove Bird-Friendly Features: When birds are nesting in unwanted places, it may be possible to discourage their efforts by making the overall yard less welcoming. Removing their preferred foods or opting for feeders they cannot access as readily, for example, deprives those birds of the resources they need to raise their young, and they will be more likely to move on to more suitable nesting sites.
   
• Provide Safer Spaces: Encouraging birds to nest in other areas can be effective at discouraging them from less welcoming spots. Add bird houses and nesting material in different areas, and birds may be willing to nest in more appropriate locations rather than work harder to build a nest where it isn't wanted.

Birds can be persistent, and the best way to discourage nesting birds is to use several methods and be vigilant about removing nesting material when birds start building their nests. After the nest is complete and eggs are laid, however, it is illegal to disturb the nests, so birders must be equally persistent in keeping birds from nesting in poor locations.

What Not to Do

At no time should any techniques be used that could potentially harm birds, even if they insist on nesting in the most inconvenient place possible. Responsible birders will never use poisons, traps, spikes or sticky gel to deter birds, as all of these methods could result in injuries, illnesses and even fatalities, and there is no way to ensure that only the undesirable birds are targeted by such cruel options. Fortunately, with so many other techniques available, it is easier than many birders realize to discourage nesting birds safely and comfortably for both birds and humans.

Photo – European Starling Nesting © John Haslam