May 19 2008
The two peregrine chicks at Gulf Tower were banded Monday morning – 1 male and 1 female.
Beth Fife of the PA Game Commission collected the chicks from the nest but not before she was attacked by the mother peregrine Tasha2, pictured here on my cellphone. (I like this picture because it gives you a sense of how large an adult peregrine is.)
Peregrines are very protective of their young – as we are of our own – but Tasha2 is so brave and aggressive that she’s willing to hurt herself in the attempt. To protect her and everyone else Beth captured her first. Then as Beth reached to collect the chicks, Louie, the father peregrine zoomed past and hit Beth’s head. This was a surprise! He used to stay far from the action at banding time.
The chicks and Tasha2 were brought inside. Erin Estell of the National Aviary kept Tasha calm by holding her in this special way. Tasha’s babies were given a health check by the National Aviary veterinary staff. Then the PA Game Commission weighed the chicks (to determine their sex) and applied the bands.
Peregrine leg bands are color-coded bracelets – in this case black on top, green on bottom. The numbers and letters on the bands are big enough that you can read them in a photograph (as shown here) or through binoculars if you’re not too far away. When observers report a bird’s bands and location, we learn where it went after it left Pittsburgh. This is scientifically useful and it’s how peregrine followers find out about peregrine alumni.
So how does a peregrine’s weight determine its sex and why do we need to know their sex when they’re banded? Female peregrines are always larger than males and they weigh more (the Gulf Tower female chick weighed 1100 grams, the male weighed 750g). Females’ legs are also bigger in diameter so by weighing the birds the banders know which size band to use.
The banding didn’t last long. In about half an hour, mom and chicks were back in the nest. The chicks slept all afternoon to make up for the excitement.