Polk County Conservation

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Bird Questions

  • There is a pair of barn swallows nesting above the door at my business. They have swooped down on customers a few times as they walk through the door. I’d really like these birds gone. Can I safely move the nest? What’s the best thing to do?


    Swallows usually return to the same nest location each year. To discourage nest construction in that location, install barriers made from plastic sheeting, vinyl strips or fine-mesh wire. These barriers should be installed before swallows arrive in the spring.

  • I was thinking about putting up a purple martin house on my property because I’ve heard they eat a lot of mosquitoes. I thought it would be an environmentally friendly way to get rid of mosquitoes in my yard. My husband thinks it’s a crazy idea, what do you think?

    I appreciate you searching for an environmentally friendly way to rid your yard of mosquitoes, but purple martins aren’t the answer. The notion that purple martins are mosquito eating machines has been widely circulated by purple martin house manufacturers for years. There have been numerous studies on the diet of purple martins and the studies revealed martins prefer larger insects such as dragonflies, damselflies, butterflies, moths, grasshoppers, katydids, mayflies, cicadas, beetles, flies, wasps, midges, and flying ants.

    Why don’t purple martins eat mosquitoes? The amount of energy a martin expends in capturing a single large insect like a dragonfly is minimal compared with the energy it would require to capture hundreds of mosquitoes that would equal the same amount of food as the single dragonfly. Martins and mosquitoes rarely cross paths since they fly at different heights and at different times of day. Rather than erecting a martin house to attract these insect eating birds for mosquito control, you should install one if you enjoy watching these birds and want to provide them a place to live.

  • I have lived in my neighborhood for 10 years and this has been the first spring I have heard woodpeckers drumming very loudly in the morning. I have seen a few woodpeckers in my yard before but have never heard them making so much noise. Why are they doing this?

    Woodpeckers use simple calls and drumming to communicate with one another. During spring, woodpeckers will drum to attract a mate or declare a territory. Drumming is usually used to communicate long distances so it is done on a surface with good acoustic properties like hollow branches, down spouts, or metal rain gutters. Drumming is fast paced, while foraging and excavating are slow and relatively quiet. Both male and female woodpeckers drum and it is very difficult to tell the species of woodpecker by listening to the pattern of drumming. This seasonal activity will subside as mating season passes.

  • Why are grackles putting droppings into my birdbath? Is there any way to prevent them from doing this?

    I know it can be a pain to clean out your bird bath over and over again but there really isn’t anything you can do. After their young hatch, grackles keep their nests clean to prevent predators from finding it. Fecal matter from young birds is covered with a sac like membrane which allows them to carry it away from the nest to be disposed of. Birdbaths and swimming pools are attractive disposal sites because the water reduces the smell from fecal matter.

  • Every summer most of my hummingbirds disappear from my feeder for a few weeks then come back in good numbers. The same thing happens at my neighbor’s feeder. What's going on?

    It sounds like nesting season to me. While nesting, female ruby-throated hummingbirds spend time sitting on their eggs and feeding young. Females will not necessarily build a nest near a hummingbird feeder. They do not prefer to nest in a male’s feeding territory and your feeder is probably part of one. Traveling to and from a distant feeder takes too much time away from the eggs. When the chicks hatch, they need protein to grow so the mother spends time catching insects and spiders to feed her young rather than drinking nectar. After the young leave the nest, the female may return to the feeder and bring her young with her. Male hummingbirds may be less common at feeders due to the abundance of flowers blooming during this time. So be patient and wait, the hummingbirds will return!

  • I love to feed birds, but I want to discourage grackles, starlings and sparrows that are so greedy and eat so much of the seed. What can I do?

    The first thing you can try is setting up a feeder that is specifically designed for small birds. Choose a tube feeder with small perches and no catch basin on which larger birds can perch. A cage around the tube feeder will let smaller birds through but will keep out larger birds and squirrels. If house finches become a problem at your thistle feeder, try a feeder where the ports are below the perches. Only birds like goldfinches that hang upside down to feed will be able to eat there. Avoid platform trays and don't spread food on the ground, where the larger aggressive species can access it. Don't offer seed mixes with corn, millet, or milo, which grackles and pigeons enjoy. If starlings are gobbling down your suet, offer it in a container open only at the bottom, requiring birds to feed hanging upside down. Woodpeckers, chickadees, and nuthatches do this naturally, but starlings cannot. By trying these things you may reduce the amount of food available for house sparrows or European starlings. These birds are not native to the United States and aggressively compete with native birds for food and nesting sites.

  • Are the bluebirds back yet? My son made me some bluebird boxes and I’m wondering when I should put them up.

    Yes the bluebirds are starting to come back! Males typically arrive a couple of weeks ahead of the females. Some bluebirds have already been spotted building nests in nest boxes in our Polk County parks. Bluebird boxes should be up and ready by the end of March. Good bluebird habitat includes open grassy areas with little or no under story and a few trees nearby for perching. Bluebird boxes should be spaced at intervals of about 300 feet and at least 200 feet away from wooded brushy areas. The box should be placed on a smooth metal pole at least 4 to 5 feet high. Anything lower is at greater risk for predation. The entrance hole should be directed away from prevailing winds and face away from direct sun exposure. Ideally you should check the box every seven to 10 days from late March until mid-August. Monitoring your box on a regular basis is important because you can collect important information about the nest and keep an eye out for problems should they arise. Bluebirds and other songbirds have a poor sense of smell and are not able to detect human scent, so they will not abandon their box if you open it to check it. For more information about bluebirds visit North American Bluebird Society’s Web site at www.nabluebirdsociety.org.

  • I don't ever recall seeing robins before late March in Iowa. I have seen a substantial number in central Iowa this January and February. What could cause this? What are they eating?

    I have also seen quite a few robins. Last week there was a flock of 40-50 robins in my yard devouring the berries off my crabapple trees. Robins flock together in the winter because flocks have more eyes to discover new sources of fruit. Where they find fruit, it is abundant. Lots of fruit means flock members don’t have to worry about competing. Once the flock has depleted the food source, it will move on elsewhere. Robins are a migratory bird but their migration is a bit complicated. There seems to be great variation in where they spend the winter. It is not uncommon to see them here in January or February. Cold temperatures don’t hurt most birds as long as they have a good source of food. During winter robins eat mainly berries from trees, shrubs, and vines like crabapple, cherry, plum, dogwood, sumac, and wild grape. Come spring time the males start establishing territories and the flock disbands.

  • There is a hummingbird flying around in my garage and it won’t leave even with the garage door open. Why won’t it leave and how can I get it out?

    Hummingbirds are attracted to the color red. The government requires all garage doors to have red emergency release handles. Unfortunately, these red handles look a lot like trumpet vine flowers to a hummingbird and they fly in to investigate. Hummingbirds can get confused and their natural response is to fly straight up and won’t leave the garage. After an hour, a trapped hummingbird can starve to death.

    To remove the hummingbird from your garage, try hanging a hummingbird feeder on the door opening. It may leave in the correction direction after feeding. But this doesn’t always work. If it still hasn’t left after 10 minutes, try something else. You can also try using a butterfly net to gently catch and release it outside. Sometimes, if you hold up a long handled broom or mop, the bird will land on it and you can carry it outside.

    Another technique to try is to shut the garage door, darken the windows if you have them, and turn off all the lights so the garage is completely dark. Hummingbirds don’t have good night vision and will likely flutter to the floor. Use a flashlight to find it and gently scoop it up. Take it outside away from the garage and hold it close to a hummingbird feeder. Open up your hands and it may fly right to the feeder or lie there for a few minutes until it orients itself. To prevent this from happening again, paint the garage door emergency release handle black and remove any red colored objects in the garage.

  • Something is eating the baby ducks on our pond. I saw something pull one underneath the water and disappear with it. We like watching the ducks and don’t want them to disappear. What is doing this and how do we get rid of it?

    You have witnessed part of the food chain happening right in front of your eyes! My guess is a snapping turtle is eating your ducks. They will occasionally grab swimming waterfowl from beneath, pulling them under the water and then eating them. Snapping turtles are omnivores so they also eat various water plants and animals like fish, small mammals, waterfowl, and carrion. You can legally take snapping turtles with a valid fishing license. Turtles can be taken by hand, turtle hook, turtle trap or with a hook and line. Always be very careful when handling a snapping turtle. They can lunge quickly and their bite can be very painful.

  • I saw a Canada goose at a pond the other day that had fishing line wrapped around its leg and wing. I wanted to help the bird but didn’t know how. Would you or your staff have come to take care of it?

    Unfortunately we receive several phone calls like this each summer. Birds and other wildlife can easily get tangled up in fishing line that is left on shore by anglers. Polk County Conservation doesn’t have the staff, time, and resources to respond to injured wildlife situations. However, there are several things you can do to help a bird in this situation. First, take an old blanket and toss it over the bird so it can’t see you. Carefully grab a hold of the bird and take a knife to cut off the fishing line yourself. Once the bird is free of fishing line, remove the blanket and let it go. In most cases the bird will be just fine. If it appears to have serious injury or infection in the leg, contact a wildlife rehabilitator right away. Call your local county conservation board or the Iowa Department of Natural Resources to get a listing of rehabilitators. You can also help prevent this problem by picking up discarded fishing line found along shorelines. If you are fishing and the line breaks, please try to remove as much line as possible from the water and shore. Remember to take all trash home and throw it away, do not leave it behind!

  • Isn’t it true that rice thrown at weddings is dangerous to birds if they eat it?

    This is a myth! You may have heard that if birds eat rice it will swell up in their stomach causing them to die or explode. Let me repeat, this is false! Rice will not harm birds. Many wild birds like ducks and geese routinely eat wild rice with no harm. Uncooked milled rice is no more harmful to birds than wild rice in the field. Eating rice is no different than birds eating grain like millet or wheat. Birds do not have trouble digesting rice as they have powerful muscles and grit in their stomachs to grind it up. Some wedding planners say the main reason for not using rice is because there is a risk of people slipping on it and falling.

  • When driving down the road I’ve noticed small blackbirds chasing larger birds in flight. Why do they do this?

    Red-winged blackbirds are very territorial and will attack birds, animals, or people that are too close to their nests. This behavior is called mobbing when several birds work together to harass predators like hawks or owls. Mobbing can occur at anytime of the year, but is most prevalent during nesting season. When birds mob they will often physically attack the predator, sometimes even killing the animal. The purpose of mobbing is thought to distract predators away from the nest site. Many different species of birds show mobbing behavior.

  • A house finch has built a nest and laid eggs in one of my hanging flower baskets. I noticed that there are a total of four eggs in the nest, three similar looking and one slightly larger different colored egg. Why is there an odd looking egg in the nest?

    It sounds like a brown headed cowbird has laid an egg in the nest. Cowbirds are considered a parasitic species because they do not build their own nest. Instead they lay their eggs in the nests of other birds and rely on them to hatch and raise their young. A cowbird will lay one egg in a nest and knock one of the other eggs out of the nest. Some birds like the house finch, will accept the egg and raise the young cowbird as one of its own. However, some host birds will kick the cowbird egg out of the nest, desert the nest, or build a new nest over the cowbird egg.

  • I’ve noticed that robins are back and had a few questions. Do they return to the same yard every year? If so, do they reuse the same nest every year? I removed a robin nest from my tree last fall and am now wondering if they would have reused the nest?

    American robins may return to the same general area but not necessarily the same yard. Male robins start to arrive in Iowa in March to set up their territories. Males will sing heartily to advertise their presence and will physically attack other males in their territory. Females arrive a few weeks later to choose a mate. The pair forms a bond that lasts throughout the summer.

    A female robin will build a nest out of mud and grasses with occasional help from the male. Robins lay two different clutches of eggs during the summer. They will reuse the same nest during the summer, but will not reuse the same nest the following year. Some abandoned bird nests may be used by other types of birds.

    You also bring up an important point to address. All migratory birds as well as their eggs, feathers, and nests are protected by federal law under the Migratory Bird Treaty Act. This means you can not harm or possess migratory birds, eggs, feathers, or nests. So please do not remove bird nests from your yard!

  • I enjoy feeding birds in my yard and I have always wondered why some birds like goldfinches change colors in the fall and winter? Also, what’s the best way to clean out my birdfeeder?

    In some bird species, males and females are different colors. Male birds are brightly colored to catch the attention of a female during mating season. Female birds are duller in color because they spend a lot of time on the nest. Many male birds turn a dull brown color in the fall when there is no need to mate. During fall the bright feathers gradually fall out and are replaced by duller colored feathers.

    Now is a good time to clean your feeders, in fact you should try to clean and disinfect them once a month. Use a mild bleach solution to disinfect the feeder. Completely immerse the feeder in the bleach solution for 2-3 minutes and allow it to air dry. Regular cleaning helps prevent disease. Also rake and sweep up the seed hulls under the feeder where mildew and moisture accumulates.

  • We have two small lakes on our property and would like to install some wood duck boxes. We built the boxes following plans supplied by Ducks Unlimited, but now we need some information on installation. How far from shore? How high above the water? Any special directional orientation? How far apart? Your help will be gratefully appreciated.

    I’m glad you are putting up wood duck boxes! This is a great time to install them. Nest boxes have helped wood ducks make a remarkable recovery during the last 30 years. They provide relatively safe places for wood ducks to raise their young.

    Wood duck boxes placed in the water should be on posts at least 3 feet above the high water mark. To minimize access to the nest box by predators, metal predator guards should be placed on the post below the nest box. It’s best to scatter nest boxes throughout the woodland and wetland habitats so that they can’t be seen by one another.

    If you are placing them on land, post them at least 20 feet high to a tree. Boxes on land should be 30-100 feet from the waters edge because boxes at the water's edge are more vulnerable to raccoon predation. The entrance hole of the boxes on land should face the water. For boxes placed in the water there is a slight preference for the entrance to face south and west. Be sure to place a few handfuls of wood shavings in the bottom of the box. Nest boxes should be cleaned and maintained once a year.




  • I recently moved to Polk City and I drive over Saylorville Lake everyday and noticed some huge white birds on the water. What are they?

    Those birds are American white pelicans. White pelicans migrate through Iowa twice a year. Saylorville Lake is one of the largest resting spots for migrating white pelicans in the United States. Over 10,000 pelicans migrate through the area. Pelicans start arriving at Saylorville Lake from Canada and the northern U.S. in late July-early August. During their fall migration, they spend several weeks at Saylorville Lake feeding and resting. White pelicans diet consists of fish, amphibians, and crustaceans. Up to 4 pounds of food a day is consumed. By late September-early October most of the pelicans will have flown south to the Gulf Coast for the winter months.

  • I enjoy watching and feeding the birds in my yard. However, my cat kills at least 2-3 birds a week. I hate to keep my cat indoors, she loves it outside. Is there any way to keep my cat from doing this?

    Free roaming cats have a huge impact on wildlife. There are an estimated 60-90 million pet cats and millions of stray and feral cats in America. The number of birds killed per day is in the millions. Cats are natural predators. Birds and rodents are among their favorite prey. To prevent your cat from killing birds, you could keep your cat indoors. Outdoor cats face many more risks than indoor cats. Outdoor cats are exposed to serious infectious diseases, like rabies or feline leukemia. Outdoor cats can also get fleas, ticks, and other intestinal parasites. Coyotes, great horned owls, and other wild animals are known to regularly kill and eat cats. Cats that spend time outdoors require more medical treatment and their life spans are much shorter compared to indoor cats.

    If you do let your cat outdoors, keeping her well fed will not keep her from hunting. Hunting is a natural instinct. Attaching a bell to your cat’s collar will not scare birds away. Birds do not associate a ringing bell with being stalked. One product that seems to work well is the CatBib. The CatBib is attached to the cat's collar and hangs loosely over the cat's chest. It works by gently interfering with the precise timing and coordination a cat needs for successful bird hunting. The CatBib is a triangular shaped piece of thin neoprene, backed on both sides with nylon. Cats should only wear it when outside. For more information about CatBib, visit www.catgoods.com.

  • I’ve seen several baby birds hopping around on the ground in my yard and my dogs keep pestering them. In fact they’ve actually killed a couple of the birds. If I pick up a baby bird and move it to a safer spot, will the parents still be able to find it?

    Yes, the parents know exactly where their young are. Some parents are so aggressive that they will make loud noises and dive bomb animals that get to close to their young. Right now many baby birds are leaving the nest and learning to fly. Often times they end up on the ground. As long as they are hopping and have feathers, they will be fine. However, if you think a dog or cat may harm the bird, please move it to a safe location. Under a bush or in a flower bed will be fine. If you find an injured bird, do not try to care for it yourself. There are several wildlife rehabilitators in central Iowa who care for injured wild animals. Contact the Polk County Conservation office at 515-323-5300 and we can give you a list of phone numbers to call. It’s against the law to keep wild animals if you don’t have permits, even if you plan to release them.

  • I love hummingbirds and would like to attract them to my yard. What should I know about hummingbird feeders before buying one?

    Ruby throated hummingbirds are the only species of hummingbird found in Iowa. They drink nectar from all colors, shapes, and sizes of flowers. Hummingbirds also spend a lot of time catching insects in the air, off leaves and right off of spider webs. Putting up a hummingbird feeder is a great way to attract them to your yard.

    There are many kinds of feeders on the market. Most of them have flowers or red parts on them so they are attractive to hummingbirds. You will want a feeder that will be easy to clean. Start with a smaller one, until you have birds that are regularly emptying the feeder. Feeders are best placed near flowers where they may already be feeding. Try to place them out of the wind and in the shade. Hummingbird food is very easy to make on your own. Use a ratio of 1 part sugar (not honey) to 4 parts water. Boil together for 1-2 minutes and cool. No need to add red food dye to the solution. This ratio approximates the ratio of sugar to water in the nectar of many flowers. The sugar water solution can spoil easily in hot weather. Replace the solution every 2-3 days and clean out the feeder with hot water. Hummingbirds may not use your feeder if you don’t have many flowers, bushes, or trees in your yard.



  • There is a male cardinal that repeatedly flies into my windows. How can I make the bird stop this annoying behavior?

    Male cardinals are very territorial and will scare away other male cardinals in their territory. Your cardinal is seeing its reflection in the window and thinks it is another male bird, so it repeatedly attacks its own reflection. There are a few ways to deter the cardinal from this behavior. Tape 2 to 3 metallic streamers to the top of your windows. Tape the other end of the streamer to the bottom of the window. It should hang loosely to wave in the breeze. You can also try sticking several stickers to the outside of the window. The streamers and stickers will break up the reflection in the window and hopefully your cardinal will stop attacking its reflection.

Contact Us

Administration Office
11407 NW Jester Park Drive
Granger, IA 50109

P: (515) 323-5300
F: (515) 323-5354


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