When bird banders catch birds, they do more than put aluminum bands on the captured bird's legs. Many measurements are made that can be used to compare species and subspecies, sort out difficult to identify birds, compare males to females and older birds to younger birds. Measurements have been standardized to allow reasonably accurate comparisons from one bander to another. Measurements are always made using the metric system.
Some Definitions
Wing chord- measurement of the wing from the bend at the wrist to the tip of the longest primary.There are several standard measurements that are made of bird bills. Very often it is the bill of a bird that is the first structure to changes as a result of natural selection. This makes the bill size an important criteria for assigning species or subspecies status to closely related groups. The diagram below shows the most commonly used measurements.Exposed Culmen- the ridge along the top of a bird's bill.
Nares- the breathing holes at the top of the bird's bill.
Tarsus- the part of the leg between toes and the tibia where bands are usually placed.
Tibia- the part of the leg between the tarsus and the femur where secondary bands are sometimes placed.
