Winter tagging - Evening Grosbeaks

[DeGroote, Lucas]

Hello Motus users,

 

We’ll be tagging Evening Grosbeaks in Western PA once again this winter and we couldn’t have picked a better year.

 

https://finchnetwork.org/wintering-evening-grosbeak-movements

 

If possible, please try to keep your stations running through the winter.  We like to check our stations in November to download data from migration and make sure they’re still operational.    In addition, we often unplug one of our antennas to reduce the power demand and chance of brownouts from shorter and cloudier days.  We’ll plug them back in Feb/Mar when we once again download data and do our pre-migration checks.

 

Sincerely,

 

Luke DeGroote

Avian Research Coordinator

Powdermill Nature Reserve

Carnegie Museums of Natural History

Office 724-593-5521

Cell 724-771-3919

 

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[David Yeany II]

Hi Everyone,

I am collaborating with Luke DeGroote on the evening grosbeak winter movement study. On 17 Dec 2020, I deployed nanotags on 6 evening grosbeaks in the Allegheny National Forest region of Western PA. Three of those tags were the new Lotek Solar Nanotags (NTQB2-S) (see attached photos). I am wondering about a couple things:

1) What are thoughts on the solar cells' capability to charge with overlapping feathers? Should feathers be trimmed to enable better charging until molt and regrowth? I did not trim any feathers on these birds, but would consider it for the remaining solar nanotags and CTT Life Tags we have to deploy.

2) What are recommendations on harness attachment materials? I went with our elastic thread loop harnesses with Loctite glued knots. I haven't found crimp beads that I've been satisfied with for the stretch magic thread, plus that process may be a bit difficult when working solo, as is the case now.

I do have concerns that the grosbeaks are capable of clipping the harness or transmitter with their powerful beaks. However, we did collect Motus data on more than half of the 18 evening grosbeaks we tagged in 2018-19.

Thanks and happy to be part of this group!

David

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David Yeany II
Avian Ecologist
Pennsylvania Natural Heritage Program
Western Pennsylvania Conservancy

dye...@paconserve.org 

Cell: 814-221-4361

[bdossman]

Awesome project! 

1) I don't have direct experience with the solar tags, but for sure anything that blocks light to the sensor is going to hamper the recharge cycle. How serious those implications are probably depends on how long it takes those solar cells to charge the battery. If it's a quick recharge, then small light disruptions aren't going to be that detrimental because the tag has 12 hours of daylight to recharge. If the charge cycle is relatively slow, then those disruptions are going to be a serious issue. Will Lotek provide details about the charge cycle and what their thoughts on this are? If not, you could test this yourself with an extra tag if you have any. I'm sure the results will be of interest to all on this group!

2) I have had good success using the larger diameter 1mm elastic nylon with multi-year deployments. And we've had great success using the stretch magic using multiple harness securing methods (knot, crimp beads, & hot melting). If you haven't tried it already, one approach soldering the ends of the stretch magic together to create standard size harness (based on an individuals size) that can be slipped on in the field. Takes a little practice to create consistent harness but simplifies the process so that a person can tag a bird solo. Other materials to use (especially if grosbeaks are particularly bad) could be teflon. Alot of collaborators utilize teflon harnesses for the larger satellite tags with great success. Amy Scarpignato (Georgetown) also suggested a material by the name of Spectra which I believe is a high tensile strength material that might be really resilient to Grosbeaks. 

To be honest though, I'd be more concerned with Grosbeaks pulling off the antenna rather than the harness!

Hope this helps! I'm sure others in this group will be able to provide other useful ideas and notes. 

[Aubry, Yves (EC)]

All the very best with your project, I hope our antennas in Quebec will capture some signals of your birds next spring.

1)      One note from past experience with Bicknell’s Thrush VHF tracking about the type of material used for the antenna. Our first sets of transmitters had a stiff antenna that seems similar to the one I saw on your pictures. One problem we had is that the birds did try to remove the antenna and in doing  so they curled it. The antenna became a problem thereafter and impaired the movements of the birds when moving through the branches. We even successfully disentangled  one of them which had the antenna caught under a small piece  of protruding bark on a branch quite high up a tree . You must test your material used for the antenna first to make sure it will stay straight even if birds are pulling them with their beak. If a thrush can curl it, I really suspect that a grosbeak will do it too according to the material used for the antenna.

2)      About Teflon string or ribbon for the attachment, again based on my experience with thrushes, we recaptured birds with geolocators on their back one year after deployment and the Teflon was holding by a few threads only, the birds were likely pecking at it. After that season we used Dacron fly fishing back lining for the attachment but, of course, new material could be used particularly if you have a good stretching one which will resist to the Evening Grosbeak pecking.

Yves Aubry, Canadian Wildlife Service

 

 

De : motu...@googlegroups.com <motu...@googlegroups.com> De la part de bdossman
Envoyé : 21 décembre 2020 13:03
À : Motus Wildlife Tracking System <motu...@googlegroups.com>
Objet : [motus-wts] Re: Winter tagging - Evening Grosbeaks

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[Sean Walls]

Great to see the tags on such smart looking birds.

In response to the question about shading of the solar cells: certainly keeping them free from feathers is optimal, and all attempts should be made to do that.  However, this tag will last for weeks without any sunlight.  Therefore, unless a solar cell is permanently covered, we don’t expect that the tags will stop very often.  

I hope that helps,