ok. thanks to everyone for the replies so far.
it sounds like it is helpful to report banded / tagged animals. so i went ahead and sent a note to the Loggerhead Shrike Working Group (since it was recommended to contact the most specific group first), and i’m looking at the form for the USGS Bird Banding Lab. (that latter form is more complicated, and i was looking for a place to report a more detailed location than just state. i can’t seem to find it, but maybe i’ll see if i come back to it later today. or maybe they just don’t care about the location?)
i think it’s a transmitter, but i’m not sure. in the first photo, it sort of looks like there’s a long thing (about 1.5x the length of the bird) poking out of the bird’s butt. i thought maybe fishing line at first, but it looks more rigid than that – like an antenna, which i’m assuming is attached to a transmitter. it looks like the antenna is going down the center of the bird’s back or maybe offset slightly to the right, and the bird might be holding its tail slightly to the left. i’m not sure.
i see green over red on the left leg and silver (federal?) over yellow on the right leg. i looked briefly at a loggerhead shrike banding manual (http://www.nabanding.net/wp-content/uploads/2018/11/NABC_LoggerheadShrikeBandingManual_2018.pdf), but as one uninitiated in the banding arts, i don’t really understand it. i think page 9 is telling me that the yellow band could mean the bird was tagged in Texas in breeding season 2018, but then the red band could also mean the bird was tagged in wintering season 2019. so who knows? i guess if it the bird was banded somewhere else, that would be nice to know, but it’s probably not worth it (for me personally) to spend too much time trying to crack that code.
UPDATE (later same day):
i added a report to the USGS BBL, too. it did eventually let me add coordinates by picking a point on a map, after selecting country, state, and federal management area. not a great user interface / workflow, in my opinion, but it is what it is.
here was the initial stock reply by USGS BBL:
There is no need to respond to this email. If you have any questions, comments, or changes please send an e-mail to: email@example.com. Be sure to include the Marker Reference ID from this email and any necessary details.
As you probably know, these markers are used by researchers to address many questions regarding bird movements and other aspects of their life history. They enable researchers to track movements of individual banded birds without the need to recapture them. The banding and color marking of birds is conducted by a variety of researchers, some with State, Federal, NGO, or university affiliations. Our office authorizes these projects, but is not directly involved in them.
We receive thousands of these reports each year and attempt to respond to the sighters with information on each. However, due to various reasons, we are often not able to. Each bird with a color marker is also wearing a metal Federal leg band, which bears the 9-digit number that is the code by which we ultimately store our data.
There are two possible responses to these reports:
We will be able to match the marker to an individual bird (by leg band number), and enter your sighting information into our database, producing a certificate that will give you all the banding information along with your sighting information.
We will be able to match the marker to a bander, but not an individual bird, in which case we will contact the bander asking him/her to explain the nature of the project and what they have learned from the marking.
We cannot predict or control the nature of the response you will get from the bander, although we do make them aware that color marking authorizations carry with them an obligation to respond to the public. Many color marking projects are designed to study only local movements, and the bander may not be interested in reports from afar.
Because there can be several steps involved in resolving these reports, the process may take a long while. Please do not report the marker a second time! If we are unable to match the marker you reported, we will notify you by e-mail. This is, unfortunately, a common outcome, due to the fact that colors fade, markers fall off, codes are misread, etc.
Your interest, cooperation and patience are greatly appreciated.
USGS Patuxent Wildlife Research Center Bird Banding Laboratory, http://www.pwrc.usgs.gov/bbl