Field Journal 4

Date - 03/20/21
Start time - 1:50 pm
End time - 3:20 pm
Location - Mt. Philo, Charlotte, Vermont
Weather (temperature, wind speed/direction, precipitation) - 50°F, 5-10mph wind from SW, sunny
Habitat(s) - moderately dense deciduous forest with beeches, birches, and some cedars at the base; heart-leaved birch forest with large openings towards the top; cedar and pine clusters on rocky outcrops at the summit

The two nuthatches I saw were busy avoiding hikers and birders, so I didn't get to watch them communicate for too long. I heard them calling back and forth with what AllAboutBirds describes as a nasal "yank", which I think is accurate. From what I researched, nuthatches live in pairs year-round, so I probably saw a male and female foraging together. They both flew away from where I spotted them at the same time, which is why I think they were communicating and not just making noise. I didn't get to watch them long enough to read their body language, but I read about nuthatch physical communication. They raise the feathers on their back, spread out their tails, and flick their wings when they're agitated. To communicate that they are giving up a confrontation, they raise their beaks and tails while lowering their wings.

The nuthatches and raven (or crow) had very different plumages. While the corvid was a uniform shiny black, the nuthatches had white bellies and cheeks, gray backs, and a black (male) or gray (female) cap. The corvid's feathers are strengthened by the melanocytes that give them their black color. Black plumage stands out on snow, leaves, and dead tree trunks, so the corvid's feathers aren't serving as camouflage. It's possible that because of their size (raven) or aggression and tendency to flock (crow), the corvid doesn't need to hide to avoid predation.
The nuthatch's dark back and light underside create a kind of camouflage known as counter-shading. While the exact function is debated, counter-shading helps birds to match their background from above and below, and it also breaks up their silhouette from the side. Since nuthatches are much smaller than crows and ravens, they may rely more on camouflage to avoid predation.

The corvid was perched in a dead pine tree when I saw it. This time of year, many mature ravens are building nests and getting ready to raise young. This one could have been taking a break, or it could have been immature and not nesting this year. The nuthatches appeared to be foraging. They could have been looking for fresh food as the forest thaws, or they could have been retrieving seeds and insects cached behind tree bark before winter. Most nuthatches breed in May and June, so it's unlikely that this pair was building a nest yet (and I didn't see them with any materials).

I tried spishing at the nuthatches, but they were already on the move by the time I got around to it. I don't think that's what drove them away, but it certainly didn't attract them.

Posted on March 22, 2021 08:55 PM by