A newly installed Motus antenna in Prineville’s Crooked River Wetlands will help biologists and the general public better understand the migratory patterns of small wildlife species such as birds, bats, butterflies and dragonflies.
“Migration is a mystery in many ways,” said Kalysta “Kaly” Adkins, regional diversity biologist for the Oregon Department of Fish and Wildlife. Though researchers know a lot about the breeding and wintering grounds, how wildlife travel between these areas is less well known. “The management of species, especially vulnerable ones, has to include their migratory routes.”
The travels of a GPS-collared male gray wolf, OR-7 or better known as Journey, highlighted his incredible sojourn from the Wallow Mountains to the southern Cascades was well documented thanks to his satellite-linked GPS collar. But, tracking the movements of smaller wildlife species such as birds, bats, and insects, has been a challenge in the past due to weight restrictions of the tracking device.
“The device can’t be more than 2-3 percent of a species’ body weight,” said Adkins. For a Lewis’s woodpecker, a species Adkins studies in Oregon, their body weight varies from 88 to 139 grams (3.1 to 4.9 ounces), so as to not disrupt the daily activities of such a bird, a tracking device would have to weigh somewhere around next to nothing. Green darners, a large dragonfly, are outfitted with a NanoPin tag that weighs around 0.15 grams (1/200th of an ounce).
Motus Wildlife Tracking System, is a program of Birds Canada, the largest avian conservation-oriented non-profit in Canada, that launched in 2014 using a radio telemetry system made up of tiny radio tags, antennae and data recorders. Motus isn’t an anacronym but means “movement” in Latin.
“Motus has allowed a revolution in the world of individual tracking of particularly small wildlife species,” said William Blake, American Bird Conservancy’s Pacific Northwest Regional Motus coordinator in a presentation to the Duval Audubon Society. “Motus is a collaborative approach to radio telemetry.”
Telemetry technology for species that weigh under 100 grams (3.5 ounces) includes lightweight radio nanotags, called coded VHF tags, that work on the same frequency and emit small bursts of a unique Morse code-like signal, specific to the individual species, which can be picked up by automated receiving stations which operate 24/7. The lightweight “loop tags” have a small loop harness that fits over a species’ wings like a backpack. Developed by two companies: Lotek and Cellular Tracking Technologies, the tags run on a battery, solar power, or some hybrid form depending upon the weight and size of the tag. A Bluetooth version of a tag is being developed which would ping cellphones and have an app which records the data which is available to anyone on the Motus website.
“I jumped in in July, 2025 after learning about these systems,” said Gordon Wetzel, East Cascades Bird Alliance treasurer about his “Motus moment.” With the help of the OSU-Cascades HERS lab (Human and Ecosystem Resilience and Sustainability lab), Wetzel set out to test radio interference at several locations in Central Oregon that could be appropriate for a tower. “I checked the obvious places like Hatfield Ponds, Redmond Sewage Ponds, Tumalo Reservoir and others,” Wetzel said but most had high levels of interference. After a field trip to the Deschutes Land Trust’s Ochoco Preserve, Wetzel focused his efforts across the river to the Crooked River Wetlands Complex in Prineville.
With the help of Chuck Gates, president of the Friends of the Crooked River Wetlands Complex, Wetzel got permission to test and then install an antenna at the facility.
The wetlands had installed osprey nest platforms atop large poles and since the birds weren’t using the platforms, Wetzel and Gates picked one they could attach the antennae to.
The two enlisted a couple of other helpers, one a former electrical contractor, and got the antennae installed on July 24, which will be able to detect either companies’ tags or the Bluetooth signals in the future.
“As I understand it, there is a greater range of detection directionally than overhead,” said Adkins. “The idea is that the bird [or other species] will be detected on the approach or departure route in a wider swath rather than a narrow beam directly overhead.” In open country with good line of sight, that equates to about a 15-kilometer radius (9.3 miles).
“The East Cascades Bird Alliance spent about $4,000 in equipment and the Friends covered the cost of renting a power lift to work from, and the labor was free,” added Wetzel. The remaining data receiver and power supply will be installed soon, smoke permitting, and then the receiver will be up and running recording the codes of migratory creatures and helping to better understand their mysteries of migration.
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