Does a recording of a bird alarm or distress call help stop birds from eating crops?
Birds are beautiful to watch, but for farmers they can be devastating to crops. Farmers have a love hate relationship with birds. Birds eat insects that eat crops, so they are beneficial to the farm. However, fruit and seed-eating birds also eat fruit crops like blueberries and raspberries. Even if the birds do not eat the crop, they may add peck marks to the berries, making them difficult to sell except for jams and jellies.
There are a number of ways to stop birds from eating berry crops. One of the solutions is to cover the crop, either with mesh or with a large greenhouse-like blanket. Mesh can be dangerous to birds because they may get caught in the mesh and injured. Scarecrows of various sorts are also an option, as is the placement of pretend predator birds on the sides of the field. Another interesting solution is the use of sound to scare birds. This is a low impact and inexpensive way to scare away birds using predator sounds or using the sounds that bird make when they are afraid.
- Bird guide for your area
- Recording of a distressed bird call for one problem species of bird
- CD player
- Large speaker system
- Flagging tape
1. Visit the farm site to observe the interactions between the birds and the crops. Can you observe the birds eating the crops? What are they doing?
2. Mark out a specific area with flagging tape. Make this area as wide as you can see, ideally about 20 feet by 20 feet. Sit in one location for an hour and tally the number of times you see birds moving into the area.
3. Visit the site a second time at the same time of day. Make sure that the weather is the same as the first time, since this can impact bird behavior. This time, set up your stereo and play the distress call for an hour. Sit in one location for an hour and tally the number of times you see birds moving into the area.
4. Repeat the two processes as many times as you wish.
5. Determine what birds you saw each day and make a note of their behaviour. Create a bar graph for each day with the bird species at the bottom and the number of that species along the side. Compare the two days. Did the distress call make a difference?
6. As an extension, you could add a second person and they could set up a second bird observation area at the other side of the field, away from the sound. They could track birds in that area as you track birds in your area to determine whether the birds simply move to another part of the field when they hear a distress call.
Terms/Concepts: What are the problem bird species in your area? Talk to farmers; What do these birds sound like when they are alarmed?
Birds of North America Online Database. http://bna.birds.cornell.edu/bna/
$5 for a 30 day subscription – includes sound files, videos and pictures of North American birds.