ID Challenge: Greater and Lesser Yellowlegs

It’s fall migration time and many birds are gearing up for their trek south. Consequently, they may not be in the habitats where they’re usually found during breeding season. Many of them are also sporting their non-breeding plumage or are in some phase of transitioning between plumages, making it difficult to distinguish between one drab brown or grey bird and another. What’s a birder to do?

As an intermediate birder working to become a master birder via the Audubon Society Master Birder program, I want to share with you some tips I’ve learned to help push you to the next level in your own birding adventures. This is the first in a series I call “ID Challenge.”

Telling one shorebird from another is one of the big headaches for birders of any skill level, especially this time of year. While you wouldn’t expect Colorado to have many seeing as it’s fairly far from either coast, the state has a good number of these plucky birds, both resident and passersby. That’s probably because “shorebird” is a pretty deceptive term. While some do enjoy a day at the beach, many shorebirds are just as happy with a rocky stream bank, mudflat, or even a grassy field.

Greater Yellowlegs in background with Lesser Yellowlegs in foreground. Photo by Claude Nadeau/VIREO.

A classic problem in shorebird ID is distinguishing between two very similar long-legged shorebirds, the Greater (Tringa melanoleuca) and Lesser (Tringa flavipes) Yellowlegs. As their names suggest, both Yellowlegs have bright yellow legs. These long, yellow legs along with their lanky bodies help easily set them apart from other shorebirds, but what about differentiating between the two species themselves? Their plumages are very similar, so there’s no help there. It’s easy to tell them apart when they’re together just by size, but what happens when you see them alone?

Lesser Yellowlegs. Photo by Dennis Paulson.
Greater Yellowlegs at Twin Lakes Park in Gunbarrel, CO. Photo by Jamie Simo.

An easy way to tell a Greater Yellowlegs from a Lesser Yellowlegs is by looking at the bill. Is it thick and blunt-tipped with, possibly, a slight up-curve? If so, you probably have a Greater Yellowlegs on your hands. A Lesser Yellowlegs has a finer, straight, and more pointed bill. The clincher though is the length of the bill. The Greater Yellowlegs’s bill is 1 1/2 to 2 times the length of its head while the Lesser Yellowlegs’s bill is about the same length of the head or just a tiny bit longer.

But what if the bird isn’t cooperating and won’t give you a good side profile or you still can’t quite decide? Another way to tell the two apart is by their voice. Both birds are fairly vocal and both give off short whistles, but the Greater Yellowlegs gives off a greater number of whistles, usually 3-4 in quick succession. The Lesser Yellowlegs, however, gives off a lesser number of whistles, usually 1-2.

So, armed with this knowledge, go forth and see if you can find some Yellowlegs before they’ve all headed south for the winter!

Spotlight on Parks: Rocky Mountain National Park

Fall is upon us and so, before snow prevents easy access between its west and east sides, I decided to do a pilgrimage to Rocky Mountain National Park. Rocky Mountain is the grand daddy of all Colorado parks. Established in 1915 and celebrating its 100th birthday on September 4, Rocky Mountain National Park is a national treasure. The park encompasses 415 square miles of montane forests and lakes to tundra and grasslands.

Clark's Nutcracker at Rainbow Curve in Rocky Mountain National Park. Photo by Jamie Simo.
Clark’s Nutcracker at Rainbow Curve in Rocky Mountain National Park. Photo by Jamie Simo.

High atop Trail Ridge Road, I saw chipmunks, dark-eyed juncos, and Clark’s nutcrackers at the pull-off called Rainbow Curve. The animals were really close, but that’s unfortunately because people were feeding them.1  While I’ve had good success seeing pika at Rainbow Curve last year, late August isn’t as reliable a time of year to see them as July. A better place to see them is farther along Trail Ridge near Rock Cut Trail. I saw a couple scurrying along there among the rocks as well as a pair of yellow-bellied marmots. I also saw an American pipit picking around, bobbing its tail (pretty diagnostic behavior).

My ultimate goal during the tundra expedition was to finally see a ptarmigan. According to the ranger at the Alpine Visitor Center, a hen and some chicks had been seen near the pond at Medicine Bow Curve, but even with my scope and binoculars in hand, I came up empty. Ptarmigan prefer to blend in with the black and white rocks that they resemble at this time of year, so it’s possible they were there and just invisible to me. One day I’ll see you, ptarmigan!

Moose at Rocky Mountain National Park. Photo by Jamie Simo
Moose at Rocky Mountain National Park. Photo by Jamie Simo

Probably the most exciting thing on this trip was getting a good view of a group of 3 moose, two young bulls and a cow, close to the road on the western side of the park. The western side of Rocky Mountain is a great place for moose because it’s wetter and full of willow, which moose are drawn to. Sure enough, the moose were stripping the leaves off some willow and barely paid attention to the group of photographers eagerly clicking away. After we watched the moose eating their dinner, we went to get our own.

Driving back through the park afterward was eerily beautiful. The moon was huge in the sky and gave just enough light to glimpse herds of elk crossing Trail Ridge road in front of the car. The lights of Estes Park sparkled like stars far below. If you’re not the camping type or the campsites are full, a great place to stay to do a longer Rocky Mountain trip is Wildwood Inn in Estes. It sports some gorgeous views, is only 3 miles from the park, and it’s a fantastic place to birdwatch, especially hummingbirds. There’s a whole line of hummingbird feeders hung under the eaves of the office building where (mostly) broad-tailed hummingbirds flit around like tiny jewels, refueling before their long journey south. Though I’ve never seen one there, bears occasionally roam around the grounds after dark too.

Rocky Mountain National Park is one of my favorite places in Colorado and I’d urge you to go visit if you’ve never been or to visit again even if you have. There’s always something new and interesting to see there. Entry to the park is $20 per car or $10 per bicycle or pedestrian. You can also purchase an annual pass specifically for Rocky Mountain that gives you unlimited entry for $40 or an America the Beautiful annual pass for $80 that will admit you to all national parks and Federal recreation lands for the year of purchase.

  1.  Feeding wildlife encourages them to depend on handouts instead of foraging so they could starve in the winter. Please don’t feed the wildlife.