Choosing a PTT

What size PTT is best ?

The general convention has always been to use a PTT weighing no more than 3% of the weight of the bird. However, we know of instances where researchers have successfully tracked birds using PTTs weighing up 7% of the bird's weight. Obviously, this may depend on the species involved; a heavier PTT may not be suitable for long-range migrants. As our PTTs get smaller and lighter, researchers are often tempted to use the smallest PTT available. However, the smaller PTT is not always an appropriate choice. Smaller PTTs are made of lightweight materials and, as a result, are not as robust as the larger models.  Particularly destructive birds, such as geese and eagles, require the largest, sturdiest PTTs they can safely carry.

Is a solar PTT appropriate?

We have been able to reduce the weight of our PTTs while extending their operational life through the use of solar rechargeable batteries. A solar PTT may be the answer to a multiyear study's requirements as it has the potential to run for 3 years or more. To successfully track birds with solar PTTs the bird must be able to tolerate a backpack attachment.

Solar PTTs need several hours of direct sunlight to charge. Charging occurs much more slowly in dim light (e.g., shade or stormy weather). The PTT's solar array must remain completely exposed to efficiently charge the PTT.  If feathers or dirt cover any part of the solar array the PTT will charge at a much slower rate.

Does your bird have long feathers and/or is it likely to preen feather over the PTT?  If so, solar powered PTTs would not be appropriate for this species. Does your bird spend time in burrows, caves or deep shade?  Solar PTTs must be regularly exposed to direct sunlight to charge, hence are not appropriate for tracking these species.

Can your bird wear a backpack?

The standard configuration for our PTTs is backpack. For GPS enhanced and solar models the PTTs must be worn as a backpack to remain properly positioned for GPS data collection and battery recharge, hence these models are not appropriate for leg bands or neck collars. We do offer implantable PTTs for waterfowl that dive.

How long is your study?

Battery powered PTTs will run until the battery is spent. Operational life is dictated by the size of the battery, hence our larger battery powered PTTs have a longer operational life than the smaller battery powered PTTs. The battery life of a PTT can be extended to cover a study period by the use of duty cycle programming. For multiyear studies, a solar powered PTT should be considered, as these PTTs have the potential to run for years (regardless of their size) provided they continue to receive adequate exposure to direct sunlight to recharge their batteries. Please see above, "Is a solar PTT appropriate."

Photo by Bob Christensen

Duty Cycle Timers
Placing an Order
Testing PTTs
Storing PTTs
Sending PTTs Back
Downloading the GPS Parsing Software  
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