Collecting the Data
After the hummingbirds are captured, they are carefully fitted with tiny aluminum bands (Figure 4) with unique numbers printed on them. The data collected on each individual bird can then be tracked to this individual band number. The data is required to be forwarded to the Bird Banding Office each year by the bander.
In the field, it is often necessary to set up a mobile "laboratory" (Figure 5) where data can easily be collected.
The basic information that must be collected on any bird banded is the bird's age and sex, if they can be determined. Luckily, this is relatively simple to determine in Ruby-throated Hummingbirds compared to some other species. See Determining Age and Sex below.
Hummingbirds are tiny, but rather sturdy creatures. Every hummingbird bander must learn a special technique (Figure 6) to handle them, which is different from the way most birds are handled for banding. Raptors too require special handling techniques to avoid injury to the bander!
To keep the hummingbirds calm during the banding process, they are placed in a special holding "blanket", which is most often made from the toe of a nylon stocking (Figure 7)!
Once the band has been fitted on the hummingbird, using special pliers (Figure 7a), data collection can begin. Wing length is precisely measured (Figure 8), which is an important indicator of the sex of the bird.
Another important indicator of a hummingbirds sex is bill length. This is also carefully and precisely measured (Figure 9).
The length of the tail is quickly measured with a ruler (Figure 10).
And finally, the weight of the hummingbird is taken (Figure 11). Ruby-throated Hummingbirds weigh between 2.8 and 3.5 grams during the summer, and can gain an additional 1 to 1.5 grams during migration! This is quite a weight gain for such a tiny bird, but is still only between the weight of a penny and that of a nickel! An assessment of how much fat the bird is carrying is also made at this point.
All this data must be recorded. The data for the Michigan HummerNet is recorded on a small palm-top computer (Figure 12) in the field, and is then transferred to a desk top computer for back up. This data is then also entered into a special computer program required by the Bird Banding Lab.