South Coast Osprey Project — Frequently Asked Questions

Ospreys on nest © Peter Gray
Ospreys on nest © Peter Gray

Why use an adult osprey instead of one hatched this spring (juvenile)?

An adult bird has already run the gauntlet of migration once if not several times, after surviving at least three summers. We choose birds that, based on the nesting information we have gathered for the past four years, we suspect have migrated more than a few times already, demonstrating robustness and experience that will prove favorable for our project.

Does trapping cause harm to the bird?

Trapping a wild animal is never benign, but with the skilled personnel on the project, we have the techniques and efficiency to minimize harm. Individual birds will also respond differently to being trapped. If we determine that our chosen bird is really not taking the experience well or has been injured in any way, we will abort and select a different bird.

What does the harness do to the bird?

The harness represents an impediment in terms of additional weight (a bit over an ounce) and bulk. However, experience shows that a strong bird is fully capable of absorbing the additional load and inconvenience.

What does the antennae do to the bird?

Again, there is likely some inconvenience but, as some of us may have observed, at times a bird has an out-of-kilter feather, or a twig, or some other debris lodged in its coat but this does not appear to hold the bird back.

Might the daily movements of the bird damage the equipment?

Experience shows that while any one transmitter may not function the full 3 years of its potential for a variety of reasons, they appear to withstand quite well the rigors of daily living attached to a hunting bird. The osprey’s fishing technique serves to protect the equipment as the bird dives feet and talon first towards its prey in the water while its body protects the equipment from impact. The equipment is water-proof.

If the equipment is not a GPS unit, as stated in the background information, how does it transmit GPS locations?

The early equipment has been improved over time such that now the transmitter is able to relay GPS-based location data. This is why positions are so accurately portrayed on the aerial maps.

What powers the transmitter?

The transmitter is solar powered. This may explain why sometimes we lose connection with a bird temporarily if there hasn’t been enough solar energy to keep it working. If the backpack remains on the bird, eventually the energy is restored to reactivate the transmissions.

How would we know if the transmitter stopped working or fell off?

After tagging a number of birds over several years, our advisors have become experienced in deducing the story behind failed or unlikely reports.  We accept the reality that this equipment, while expensive, is not infallible. We will place a numbered band on the leg of each tagged osprey so that if we lose a transmitter entirely, we will be able to detect if it is lost with the bird (i.e. both perished) or if it detached from the bird. If we see a male on the nest where a tagged bird nested, we would know if that bird was the one tagged or a different bird based on the presence or absence of the matching band.

If the transmitter falls off, what happens to our project?

If the transmitter falls off where it can be retrieved, as in on the nest or perch or some other piece of land, we will retrieve it and reapply it to the same or a different bird as deemed appropriate. If the transmitter falls off into the water such that it stops transmitting and can’t be retrieved, we will be unable to reuse it. However, as long as we acquire the least bit of data, such as information about where a bird is fishing even in a week’s time, we will have new and valuable information.  Our project is structured to be successful at different scales, each step lending more insight than the next. Tagging four birds helps extend this even more, as odds are smaller that we would lose all transmitters.