Saying Farewell to HB - removing the radio harness

Here you can see the location of HB's radio- somewhat obscured by her feathers- placed properly on her back. She has preened her antenna which is why it is kinked (Glenn photo).

Julie Shaw, CSU Chico grad student researching winter roosts sites of the saw-whet, called me and said "HB is low in a toyon, do you want to take her harness off?" HB is our remaining BCCER owl that still had a radio, for 91 days. Because the radios or so small (see earlier post "tracking the saw-whet"), they last only about 90 days-so we knew the battery would die soon. HB has been alternating in high (85') to low (3-6') perches and this day she was low. Although the radio harness or backpack is designed to bio-degrade, hers was still intact and I wanted to remove the backpack to set her free of any impediments caused by us. HB presented us with a perfect opportunity! Julie's trackers Glenn and Shannon took some of following photos-thanks!

Removing the harness

Step 1: find the bird. There she was about 6 feet high in a toyon shrub (Julie Shaw photo)

Step 2; Capture. There are many ways to capture a roosting saw-whet. I chose to use a capture technique where, with an extension pole, I place a coated loop around her head and wing. This immobilizes her temporarily while Julie then can hand catch her, as the second picture shows (Shannon photos).

Preparing to capture

HB is safely captured

And happily, Julie has safely secured HB (Shannon photo)

Step 3: Remove the harness. Next we find the harness material and clip it with scissors, and remove the backpack and radio. HB, in the second pic in this cell, is now free of her harness (Shannon photos).

removing the harness

harness-free

Step 4: check body condition. We want to check her body condition to see make sure the harness did not cause problems. Her keel (breastbone), felt fleshy on each side- indicating she was flying and eating well. We knew this though because Julie had found many pellets (regurgitated bones and fur/indigestible prey parts), and we alway saw urates below her roost, also indicating she was eating, thus hunting well. We checked her skin for potential abrasions from the material/radio- and fortunately there were none (Shannon photos).

checking the keel

checking the skin

We also weighed her and found that she was 97 grams, up 3 grams from her original mass of 94 grams! HB, a darling owl, who gave of lots of information about the wintering habits of saw-whet owls (Glenn photo).

Step 5: release. We released HB with high hopes that she would continue her success through the breeding season, likely somewhere in the Sierra Nevada Range, and thanking her for enlightening us to what habitats and prey (Julie collected almost 45 pellets that she will analyze for species composition) some saw-whet owls will take advantage of during the winter. These insights are invaluable for saw-whet owl conservation (Julie photo).

And as with any happy ending, we had a fantastic sunset as we exited the BCCER (Dawn photo)!

Tracking the Saw-whet

Our fall monitoring project has expanded to have a new component- radio telemetry and tracking. I am helping a CSU graduate student Julie Shaw, with her studies to determine winter roost sites of the saw-whet. One of our questions derived from the fall monitoring was, "where do the birds go in the winter after migrating through the Reserve?" We knew that some stayed

on the Reserve because we recaptured a few, a couple of weeks to

months later.

But now, because we have installed tiny radio transmitters on the owls (3 grams total, less than 3% of the birds body weight-see picture above that includes radio and harness material), we are able to track them to their actual locations! Julie will collect 2 years of data and then publish her results, brand new information for our region- and wonderful to better understand the ecology of our population of owls! So far we have found owls roosting on the ground like this bird,

some a few feet off the ground, and many way up in a tree- up to 85 feet, so all we see is a feathery ball, like in the picture (the bird is within the red circle).

We always like to get a good look if possible to check the condition of them and make sure their harness is fitting well. The harness will come off in about 3 months- the same time as the life of the radio battery. Most of the birds sit in good cover to protect themselves from diurnal predators like Cooper's Hawks. We got a really nice look at this bird who has had her transmitter on for 8 weeks.

Julie has been great about creating maps of the bird's locations, like this one. Here you can see a map with 4 different roost locations of one bird who was banded at the Reserve and then moved

down into Bidwell Park.