Backpacks on Birds

The month before we leave on the migration is always hectic. First you have to leave home knowing you won’t be back until December. Then there is Crane Fest and our Annual General Meeting plus all the packing of trailers and servicing of vehicles. So there is very little time for much else, which is my humble excuse for not contributing an update to the Field Journal for weeks

Before we leave, the birds must be banded and have radio transmitters fitted to their legs. Back in 2001 when we started this project, that process took a long time. Three colored bands were glued in place separately and the radio unit was fastened to the outside of all three. The birds had to be held for several minutes and while we were at it, the vet team took samples and weighed them. Being grabbed and held was an affront to the birds and on top of being sore, they were also upset at us. It sometimes took a week or more before they would trust us again and in that time they were not interested in following the aircraft. All of this took place just before the migration at a critical time in their training.

After a few years of this we decided to use a snap on radio band which can be attached in seconds without picking the birds up. The permanent bands are now fitted once they arrive in Florida when their allegiance to us is no longer critical. Now instead of indignant birds that take a week to forgive us all we get is a sideways glance followed by a few Whooping crane swear words.

Once in Florida some of the birds are fitted with PTT’s or Platform Terminal Transmitters. These are satellite devices that can tell us the location of a bird anywhere in the continent. Unfortunately this technology costs around $3500 to purchase and another $1000 per year to monitor. Satellites are not cheap.

The International Crane Foundation has been working with the University of Nebraska to develop a tracking device that uses cell phone technology. The units turn themselves on about every four hours to search for a cell signal. When they connect, they download the GPS track history of where the bird has been since the last report. Those data can be plotted on a map to show what habitat the bird was using or how far it traveled.

These units are in the experimental stage and have not yet been miniaturized to the point they can be fitted into a leg band. Instead they are mounted on the bird using a backpack. Teflon ribbon is used to cross under the wings holding the device firmly on their backs were it is soon preened into the feathers and almost disappears. The UL birds were selected for testing because we get to fly with them and can see exactly how it is functioning.  So for a couple of days cranes #4, 7 & 9-13 were not too happy with us.

Cranes can be curious or even aggressive to each other when one of them is different. We watched them closely to ensure that did not happen and were pleased to observe that nothing changed in their social order.

We did find however, after a few days of flying there were problems with the way the units fit on their backs. They sit a little too high causing drag when the birds are flying. After we noticed a reduction in their endurance, the units were removed.

This technology is very exciting and could revolutionize avian tracking at greatly reduced costs. ICF and the University of Nebraska should be applauded for their efforts. We hope the electronics that are so promising can be housed in a unit that is more streamlined for future testing.

Share Button