Tag Deployment
Everything you need to know about deploying tags
This chapter pertains to tag deployment methos in the field. For information on the management of tag deployment metadata withing the Motus system, see Tag Management.
Instructional videos on how to tag videos can be found in the next section.
We will be updating this section soon. For now, please see our PDF guide: https://motus.org/data/download/tag_deployment_methods.pdf
There are a number of researchers who opt to cut the antennas of tags when deploying on smaller animals. Basic antenna theory suggests it will decrease the effective power of the transmitter, but more testing is needed to determine the magnitude of this decrease when deployed on animals. Controlled tests have shown that OOK tags (166.380 MHz) will decrease in power with length, but are most effective when cut to specific lengths (harmonics of the nominal frequency). On the other hand, FSK tags (434 MHz) appear to decrease continuously with length, not showing better performance at specific lengths like OOK tags. These tag tests were not done on animals and will likely be different in real deployments.
That being said, if you're planning on trimming one of your Lotek tags, you should aim for one of these lengths to maximize the effect power:
Frequency | Lengths |
|---|---|
166.380 MHz | 18.0 cm, 15.0 cm, 12.9 cm, 11.3 cm, 10.0 cm, 9.0 cm, 8.2 cm, 7.5 cm, 6.9 cm, 6.4 cm, 6.0 cm, 5.6 cm |
151.5 MHz | 19.8 cm, 16.5 cm, 14.1 cm, 12.4 cm, 11 cm, 9.9 cm, 9 cm, 8.2 cm, 7.6 cm, 7.1 cm, 6.6 cm, 6.2 cm |
150.1 MHz | 20 cm, 16.6 cm, 14.3 cm, 12.5 cm, 11.1 cm, 10 cm, 9.1 cm, 8.3 cm, 7.7 cm, 7.1 cm, 6.7 cm, 6.2 cm |
This table lists harness sizes for the pre-fabricated ‘figure eight’ leg loop harness method based on real sizes used on individuals tagged in the field. Sizes include the length of the entire single leg-loop, but do not include overlap with the tag. Weights can be used to help specify which harness size to use.
Please note that these are guidelines. Regardless of what sizes you find here, the harness should always be fitted to the individual. Please see a How to Tag Animals above for more information.
Species | Harness Size (mm) | Weight (g) | Sample size |
|---|---|---|---|
Yellow-billed Cuckoo | 50-61 | 43-80 | 10 |
Black-billed Cuckoo | 52 | 34 | 1 |
Hammond's Flycatcher | 29 | 9.5 | 1 |
Dusky Flycatcher | 34 | | 1 |
Say's Phoebe | 37 | 23.5 | 1 |
White-eyed Vireo | 28-34 | 9-12 | 5 |
Warbling Vireo | 33-35 | 13-14 | 3 |
Red-eyed Vireo | 39-42 | 15-20 | 100+ |
Bank Swallow | 32-34 | 10-13 | 50+ |
Barn Swallow | 34-37 | 17-19 | 80+ |
House Wren | 33 | 11 | 1 |
Eurasian Reed Warbler | 30 | 9-13 | 60+ |
Gray-cheeked Thrush | 50-54 | 26-37 | 30+ |
Bicknell's Thrush | 46-50 | 24-30 | 12 |
Swainson's Thrush | 48-52 | 25-36 | 100+ |
Brown Thrasher | 62 | 67 | 1 |
Golden-winged Warbler | 29 | 8 | 1 |
Orange-crowned Warbler | 29-32 | 8-10 | 4 |
Kentucky Warbler | 34-35 | 12-15 | 2 |
Hooded Warbler | 30-34 | 9-14 | 4 |
Magnolia Warbler | 24-28 | | ? |
Blackpoll Warbler | 33-36 | 10-22 | 200+ |
Black-throated Blue Warbler | 26-28 | | ? |
Palm Warbler | 26-34 | 9-12 | 5 |
Yellow-rumped Warbler (Myrtle) | 31-34 | 10-15 | 100+ |
Prairie Warbler | 26-29 | 7-10 | 7 |
Canada Warbler | 34 | 10-12 | ? |
Yellow-breasted Chat | 40-42 | 22-25 | 4 |
Saltmarsh Sparrow | 36-39 | 18-20 | 60+ |
Clay-colored Sparrow | 30-31 | 9-12 | 7 |
Field Sparrow | 30-32 | 12-13 | 6 |
Lark Sparrow | 32-42 | 20-28 | 1 |
White-crowned Sparrow | 44 | 31 | 1 |
White-throated Sparrow | 45-50 | 23-31 | 100+ |
Savannah Sparrow (Ipswich) | 38-44 | 21-30 | 100+ |
Eastern Towhee | 50 | 40 | 1 |
Summer Tanager | 39-40 | 26-27 | 2 |
Blue Grosbeak | 37 | 26 | 1 |
Indigo Bunting | 34-36 | 14-17 | 10 |
Painted Bunting | 34 | | 1 |
Dickcissel | 38-44 | 22-32 | 3 |
Orchard Oriole | 40-42 | 19-22 | 2 |
Aliasing can occur when multiple tags emit a signal at the same time. Sometimes these interacting signals can produce a pattern which match a different tag that is not actually present. This is due to the nature of how the unique tag ID is encoded in the signal. However, the parameters used to define these IDs are quite stringent, making aliasing only an issue in specific conditions.
To help mitigate aliasing, we recommend keeping numbers low at any given tagging site. This can be done by staggering deployments, either spatially or temporally. Most aliasing is caused by tags which have the same burst interval but a different Lotek ID. That means if you have more than one burst interval in your selection of tags, you can deploy more tags at any given site with a reduced risk of aliasing. However, do not deploy more than one tag with the same Lotek ID, even if they have different burst intervals!
Last modified 4mo ago