How Grandad Taught Me Radio Tracking

Grandad O'Donnell giving me an early lesson in wildlife and fisheries management.

When I was young and we went to my grandparents' house for Thanksgiving or Christmas, my Grandad would play a game with us called "Hot or Cold."  He'd hide a few coins around the living room while we waited upstairs, then call us down.  As we slowly worked our way around the room he'd give us the play-by-play, to indicate how close we were to the coins and whether we were going in the right direction.  "You're very cold," "You're getting warmer," and when we almost found the coins, "You're burning up; you're almost on fire!"  Radio tracking an animal works exactly the same way.

This weekend, I got to help Tiffany Sprague, an Arizona State University graduate student, radio track Mexican Garter Snakes.  The Mexican Garter Snake is a federally protected species, listed as Threatened under the Endangered Species Act.  It once occurred along many still and slow-moving water bodies in central and southern Arizona and New Mexico, but it has declined dramatically because of competition and predation by introduced species and the development and draining of wetlands.  Tiffany is trying to help this species by studying its fine-scale habitat preferences.  Knowing exactly what kind of habitat is best for this species will help land managers bring it back to the areas where it has been lost, once the non-native predators and competitors like sport fish, crayfish, and bullfrogs are under control.

This fish hatchery specializes on raising native non-game fish and on making habitat for the endangered Mexican Garter Snake.

A selection of various radio transmitters that are used on the snakes, some for larger snakes (red), and some for smaller snakes to be implanted (silver antennae) or attached externally (black antennae).

Since May, Tiffany, Kellie, and a crew of volunteers have been catching Mexican Garter Snakes and having radio transmitters surgically implanted in them.  They then released the snakes where they found them, and have been returning each weekend to monitor what the snakes are doing and especially which habitats they are using.  They use a handheld antenna to listen for pings from each snake's radio, with each snake on a different frequency.  The antennae are directional, so by rotating them back and forth, they can find which direction is "hot" or "cold:" which direction they need to go to find their target snake.

Tyler and Kellie radio tracking a snake near the hatchery.  "You're getting warmer. . . ."

Scott and Tiffany try to pinpoint the exact underground location of a brumating Mexican Garter Snake.  "You're almost on fire!"

Once we tracked down a snake, whether it was underground or not, we measured a bunch of habitat variables in the area of the snake, including slope, aspect, ground cover, temperature, wind speed, and others.  Then we randomly selected a nearby point so that Tiffany could compare the habitats the snakes chose to the ones they didn't.

Tiffany starts measuring the habitat where a snake was seen earlier in the day (pink flag), while Scott tries to determine where it has moved to.

Kellie used this one meter diameter section of garden hose to delineate the area around a brumating snake where she would measure the microhabitat.

By about 4:00, few snakes had been seen on the surface and those that were on the surface had quickly escaped into nearby holes or blackberry brambles.  I hadn't seen a snake yet, so we went back to measure the habitat at a spot where Scott thought the snake might still be visible.  This was a unique microhabitat, where the snake was in a small undercut bank at the edge of a dry pond.  Although it was similar to a burrow, it didn't go deep enough that the snake could actually escape view.  It was here that I saw my first Mexican Garter Snake, or at least saw its side.  Because they are an endangered species and because Tiffany was studying their behavior, we wanted to be certain not to disturb the snake too much or change its activity.  Scott gently peeled the grass back just enough that I could see the snake in its hole, and then placed it back, leaving the snake just as we had found it.

Scott pulls back the grass to reveal my lifer Mexican Garter Snake under the cut edge of the bank in a dried pond.

A slightly closer look at the endangered Mexican Garter Snake.

Scott and Tiffany measure the habitat in a 5-meter diameter circle around the snake using these PVC poles to mark distances from the snake at half-meter intervals.

This south-facing rocky slope was a particularly popular place for the snakes to spend the winter.  Each pink flag (at least 10 visible here) marks the location a snake was detected underground.

As the sun set and the sky got dark, most of our tracking was done for the day.  However, Tiffany is only tracking the snakes once a week, and wanted to do a bit more intensive tracking of a few select snakes to be sure here weekly data were representative of shorter time scales as well.  So each weekend, two snakes get monitored every 3 hours, 24 hours a day.  It was nearly dark when Kellie and Scott set out to track the two target snakes, and they'd be waking up every three hours through the night to check on them.  I, on the other hand, shared a great dinner with the crew and then got to head home to my own bed!

As the sky turned from blue to black, Kellie and Scott headed out to check on the movements of the two Mexican Garter Snakes that were the subject of fine-scale monitoring this weekend.

Birding Mt. Ord

Last week, my friend Jason and I went birding on Mt. Ord.  Mt. Ord is one of those places that is well known to locals, but probably rarely heard of by most birders outside of the greater Phoenix area.  It is a locally popular birding spot because it is the most accessible high-elevation site in Maricopa County, and so it is an easy place to find several bird species that can be tough to find anywhere else in the county. (Brown's Peak, part of the Four Peaks, is about 500 feet higher in elevation, but it takes hours of driving down a very rough road to reach the trailhead, with more hiking and climbing after that to reach the summit.  Mt. Ord is an easy drive in a passenger car all the way to within 0.75 miles of the summit.)

View of Mt. Ord from the highway on the way up as the sun starts to brighten the sky.

Jason and I started from his apartment well before sunrise so that we could be on the mountain when the birds were most active at first light.  It was about an hour drive to the top of the mountain.  The sun had risen before we started birding at 7:00, but it was still cold and dark because we were on the west side of the peak.  We started on Forest Road 1688, which is a convenient spot for county listers not just because it traverses chaparral and Ponderosa Pine habitats, but also because its entire length is in Maricopa County, so you don't have to worry about whether the rare bird you found was on the right side of the county line.

Almost as soon as we got out of the car,we came into a mixed flock of birds, including Ruby-crowned Kinglets, Bushtits, White-breasted Nuthatches, and a Bewick's Wren.  One of the first few birds I saw was an Olive Warbler!  This is an uncommon species in Maricopa County because there is not much of its high elevation conifer habitat within the county borders, but it is even more rare this late in the year, after most of them have migrated south to Mexico.

My lifer Olive Warbler was one of the first birds of the morning.

We continued along FR1688 and saw a lot of other specialty species of this mountain habitat.  It was a treat to compare Juniper Titmouse and Bridled Titmouse side-by-side, accompanied by a flock of Golden-crowned Kinglets.  An immature Golden Eagle soared by, showing the white patches in the wing as it glided overhead.  Brown Creepers called with their high-pitched notes from the conifers.  It was also fun to sort out the Dark-eyed Junco subspecies: we saw at least three types on this road (Oregon, Pink-sided, and Gray-headed).

This Juniper Titmouse was a bit out of place in a Ponderosa Pine, but we saw it in an Alligator Juniper, too.  This flock had a pair of titmice each of Juniper and Bridled flavors.

Although the sun was shining, it felt cold on the top of the mountain, especially with the wind blowing.  We were surprised to see not just one, but two tarantulas on the prowl.

FR1688 was fun and productive, but I also wanted to see the summit and bird the road a bit.  After a couple of hours, we headed up to the parking lot at the end of the road.  From there it was a 3/4 mile walk to the summit, with the first 1/4 mile mostly in Gila County and the last 1/2 mile in Maricopa County.  The birding was slow, but we did see our fourth Dark-eyed Junco subspecies of the day, a Red-backed Junco (a subspecies of Dark-eyed Junco that looks very similar to Gray-headed Junco and is rare in Maricopa County).  We also added Pine Siskin to the list for the day.  In total, I added 14 new species to my Maricopa County list, the biggest bump in my county list since my first month here.

This Red-backed subspecies Dark-eyed Junco is rare in Maricopa County.  It can be told from its look-alike relative, the Gray-headed Junco, by the whitish throat (contrasting more with the hood than the grayish throat of the Gray-headed Junco) and especially the dark upper mandible (pale pink on Gray-headed Junco).

The view from the top of Mt. Ord.  The Phoenix area is hard to see at this scale but is visible in the distance in the left part of this photo.