Osprey Banding

What do you do if you have a couple of hours to kill before you go into work? Why go watch osprey banding of course!
Today I met up with Mark Martell and Bud Tordoff to watch them band young osprey. This particular nest had three chicks in it. I went osprey banding with Bud and Mark in 2003 and at that time the chicks in the nest were almost too small to band. They had an unusual habit of just laying limp (photo at left) while being banded not the normal regal look a bird of prey has.

One interesting thing that ospreys sometimes do when you get to close to their nest is pick up objects like sticks and drop them, giving a fierce display of how ferocious they are. These birds did quite a bit of swooping and diving towards the professional tree climbers that scaled the pole to get the chicks out of the nest.

The first chick brought down was the smallest of the three and but still looked to be a good size. The young osprey put up a strong front lunging and attempting to bite anyone who came near (photo below), then suddenly out of nowhere the bird died. It happened so fast we could barely believe it. One second we were making jokes and in awe of how fierce the young bird was and then the next instant it was limp and lifeless.

Anyone who is as invested in bird research and study as this group is mortified by something like this. Mark said that over the years he has banded over 700 young birds and this is only the second time a bird has died out of the blue, this was an incredibly rare occurrence. Many questions were asked but no answers could be provided at the time. Seventy-five percent of the birds hatched this spring (and that's all birds not just raptors) will not survive their first year. So many things can go wrong from a glitch in the food supply, aggressive older siblings, disease, injury, etc a bird has to be in top peak condition in order to survive. Even though you know this, when you witness it up close like that you feel terrible and question yourself relentlessly.

What could have happened? Did the bird overheat? Unlikely, because ospreys have been banded in much hotter weather and this bird wasn't out of the nest very long. Was the bird ill? The vent area (where the bird poops) was clean, not showing any green fecal material build up. Since there were three birds in the nest and this one was the smallest was it the victim of siblicide? There were no obvious injuries to indicate it was being pecked at by its older siblings and the bird had a full crop (lump in the neck indicating it had been fed recently). Another possibility is that the bird had a genetic problem with its heart and it had heart failure from the stress of being banded. If that is the case the bird wouldn't have survived in the wild. If an osprey chick can't take the stress of being banded, what the heck would it have done the first time it flew from the nest or dove after a fish?

It was decided that the dead osprey chick would be taken back to The Raptor Center and a necropsy (animal autopsy) be performed to try and determine a cause of death.

The other two chicks were banded with the greatest of care. The oldest bird went through the process with flying colors. The middle sized chick started breathing heavily but Mark gave it water and noted that the breathing pattern was normal for a young bird that age (photo at left). Both made it back to the nest alive and well with their bands and we will just have to wait to see what the Raptor Center discovers with the dead chick.