Named after the abundance of camas lilies dotting the meadow blue through the long days of June, Lily Glen offers a fine sight that comes alive in the summer. This May-July, my field partner and I spent our days here with the purpose of locating and monitoring the nests of a local population of Oregon Vesper Sparrows. Our goal was to collect data on nest success for a range-wide study attempting to determine causes of declines in this at-risk subspecies unique to the Pacific Northwest. Tracking these birds took more patience than I had ever imagined, and we made slow progress finding the nests one by one. And I swear, the Vesper Sparrow is a particularly fickle little bird who is unsurpassed in misleading humans in the whereabouts of their nests!
Each day would start before dawn with a quick breakfast and lots of coffee to keep us attentive during the cold, slow mornings. The meadow was broken up into four general sections that Jen (the other field technician), sometimes Sarah (KBO staff biologist), and I would rotate through, following leads from previous attempts. Male Vesper Sparrows were quite consistent in their behavior, singing in their territory all morning and foraging on the ground with their female companion. Females were also fairly consistent in their behavior, which mostly consisted of foraging with or without their male companions, and hiding from us, nowhere to be found. We would crouch, sit, lay down, stand, roll, and crawl to try to keep the birds visible in the dense grass while remaining far enough away for them to go about their business.
Most nests this year were found by food carries to the nestlings. Both the male and female assist with this duty once the eggs have hatched, and the nestlings grow rapidly until they leave the nest around ten days later. A handful of nests were found by following a female who was observed carrying nesting material repeatedly to a general location. This method, although common with other birds when locating nests, was particularly difficult with our Vespers as they like to land on the ground some meters away from the nest and then walk or run the remaining distance undetected through thick grass. Additionally, we had a few “luck” finds, in which a nest was found by unintentionally flushing a female off the nest while walking through the meadow.
The most rewarding part of this job was after weeks of following the progress of a nest from creation to egg laying to hatching to fledging, seeing a little family of Vesper Sparrows exploring new lengths of the meadow together, learning the ropes of being a bird in the free world. Really, when it comes down to it, being a nest searcher means simply not giving up. There were many days when I, the least experienced of the field crew, after a half hour or so of attentively watching a female would give up and think “she’s not doing anything but eating.” Yet as Sarah would always remind me, you just need to be patient and wait for the birds to give you a clue. Our Vesper Sparrows have now all migrated south to spend the winter across pasture lands full of seeds and ground spared by snow. I know that we are all excited to see their return to Lily Glen next spring – and with the identifying color bands applied to dozens of individuals over the past two seasons, it will be a pleasure to see which birds return for another spring in the mountain meadows outside of Ashland.
Editor’s note: The Oregon Vesper Sparrow population is estimated to be <3,000 individuals. Along with researchers in the Willamette and Umpqua Valleys, OR, and the Puget Lowlands, WA, we are studying their nest success, survival rates, and habitat associations. Our goal is to find out how to target conservation actions to halt and reverse their population decline. The 2019 field season was supported by the Oregon Wildlife Foundation, Charlotte Martin, and the Management Studies Support Program for National Conservation Lands.