At Klamath Bird Observatory we study birds using this nifty technique called bird banding. So I thought it might be useful to take some time to explain the art of banding and its importance to the study of birds.
Bird Banding. What is it anyways? Bird banding is a technique used by ornithologists to study birds by capturing them, taking measurements and observations of captured individuals, tagging them with bands or collars, and releasing the bird back into the wild. Bird banding is usually performed in conjunction with the collection of information on the weather conditions, vegetation, and the presence of other avian wildlife in the region. The latter can be done by either standing in one point and keeping a list of what kinds of songs and calls heard or by walking a specific area to record what is sighted and heard.
Why bother? Banding birds allows scientists to seek answers to questions about the bird’s habitat, how long a species lives, the bird’s breeding condition, and population. Studies done on birds via bird banding have allowed us to understand if an ecosystem is functioning at a healthy rate. Birds serve well as an indicator species, basically meaning that a region with a high presence and diversity of bird species is likely hosting a healthy array of habitats. The reason birds are great signs of ecosystem health is because their susceptibility to environmental change is easy to observe. Should a contaminant or some factor negatively impact the region, the presence of birds will also be negatively impacted. A great example of this is the decline of Bald eagle populations due to the use of DDT in agriculture. The noticeable absence of Bald eagles caused naturalists to question why the eagle was suddenly disappearing. Investigations eventually resulted in the banning of DDT. This is, of course, a simplification of this ordeal, but a quick demonstration of how birds serve as a measure for ecosystem health. Banding birds allows ornithologists to get a sense of what birds are present in a region and how many are using a habitat. Some banding projects, like those of KBO, band over the span of the year and decades, collecting long-term data crucial to management decisions on how to protect threatened avifauna.
How do you catch them? The whole process takes only a few minutes and is always conducted with the bird’s health and safety in mind. Birds are caught with nets; which kind of net employed varies on the size and lifestyle of the type of bird the study is focused on. Mist nets are appropriate for smaller songbirds. These are ~12m x 6m nets made of a black threading string with five pockets extending the width of the net. Rocket nets are used for larger birds, like Turkey Vultures. This is an action-packed capture where you bait the net with a carcass and then shoot a net out at the bird. Waterfowl and shorebirds can be captured either with mist nets or nets released from helicopters. In both cases, trained banders are waiting nearby to and extract the bird and quickly collect the needed data to release the bird back into the wild. The process takes less than 3-4 minutes and the bands weigh less than 2% of the bird’s body weight.
Okay, congrats! You have a bird, now what? Once captured and safely removed, the banders will look at the bird’s feathers and examine the body to assess its age and sex.The bander will then collect other information of importance to the project being administered. This could include measurements of the bird’s wing, tail, beak, tarsus, and weight. Other data important to banding projects are signs of molt, blood samples, and toenail samples.
How to tell if a bird is male or female: For birds that are dimorphic, as in the male and female plumage are different year-round, the sex can be an easy guess. Most birds, however, have more subtle hints to their sex. In these cases, the banders may be able to look at the eye color or subtle plumage characteristics. If the bird is in the breeding season (ie. Spring and Summer), the bander can also gently blow on the bird’s stomach to look for a brooding patch or a cloacal protuberance. The brooding patch is a section of the stomach with featherless skin. In most species, the female will develop this in the breeding season to be able to better regulate the temperature of their eggs. A male, on the other hand, will develop a swelling in their cloacal area to hold semen. Seeing either of these morphological characters will indicate the sex of an adult bird. Outside of the breeding season, it could be close to impossible to know. Some birds just like to stay mysterious.
Bird banding is fun because it’s not only a great scientific approach for studying birds but also a wonderful educational tool. When appropriate, bird banding projects engage the public with nature through live demonstrations of bird banding. Since I don’t have the honor of hosting you in person, I will attempt to host you in a “blog presentation” with some pictures. This is a VERY small sample of what we find living in the Siskiyou Bioregion: