Thursday, October 26, 2017

Clueless Juvies

Text, photos and videos by Nancy Partlow©

Late summer and early fall can be a fun time for observing juvenile bird behavior.  One way to identify a first-year bird is by its appearance: coloration, a fading but still brightly-hued gape, puffy primary feathers (the downy ones beneath the tail being the last to go), and a corresponding lack of adult secondary feathers. 

Behavior is another way.   New birds often seem clueless.  While alert adults constantly flit around looking for food and predators, unwary youngsters  sit there like lumps on a limb waiting to be fed, like this immature Bushtit:   

When newbies start to gain a bit of independence things can get interesting.  I had three experiences in September that gave me insight into how young birds learn.    

The first bird I saw was a Virginia Rail, trapped behind a culvert fence  at one of the Capital Lake Interpretive Center's wetland ponds.  Having never seen a VR before, I wasn't completely sure it was a juvenile, but it certainly acted like one. 


I  immediately recognized the species  since the tall grass, reeds and cattails lining the CLIC's shorelines are  perfect habitat for it.  According to the Cornell Lab of Ornithology, Virginia Rails have evolved adaptations such as laterally compressed bodies, flexible vertebrae and long toes to facilitate their movements around their native freshwater marshes.

This rail was definitely being laterally compressed  in its frantic efforts to escape, as can be seen in this video: 

Virginia Rail caught behind culvert fence at Capitol Lake Interpretive Center

I was wondering if I was going to have to wade into the water to help it, so I was very glad when the bird eventually managed to release itself by flying over the fence to freedom.

The second bird I saw surprised me.  Prior to starting a walk on the CLIC's dike trail one day, Janet and I stopped to view Capitol Lake from the dock  near Deschutes Parkway.  Through experience, we have learned that this is a great place to spot birds, and that day was no exception. Just as we were about to turn away, we glimpsed something small and non-descript fly beneath the dock. I thought  it looked like a dipper but didn't believe it could be since the habitat isn't right.  As I've written in previous blogs, dippers are creatures of fast-moving waters and can be regularly seen at Tumwater Falls Park.  

When the bird broke cover,  it was definitely a dipper.  With its stubby tail, general lack of motivation and movement, we pegged it as a juvie:


I was concerned that it was hanging out where it wouldn't be able to find its customary food.  I checked the eBird lists for Capitol Lake, and couldn't find any previous sightings of dippers on any of them:

I hoped  this youngster hadn't become irrevocably separated from its family group, which I had been seeing at Tumwater Falls Park during this period. Dippers  will feed at salmon spawning areas, and the adult dippers had been showing their young how to take advantage of the bounty provided by the fall Chinook run.  I managed to film a dipper finding and eating a salmon egg in the pool below the upper falls, where a few errant salmon get trapped and spawn every year:

The final sighting I had was of a juvenile Great Blue Heron, again at Tumwater Falls Park.  The heron too seemed out of place, since herons are more likely to be found at Capitol Lake. Perhaps it had been pushed away from the lake's shoreline by adult herons with previously claimed territories.

Salmon filled the Deschutes River, and they swam in numbers at the bird's feet, shown in this video:   

Juvenile Great Blue Heron surrounded by salmon at Tumwater Falls Park

I was sure that this young heron could not eat an adult king salmon. These fish looked bigger than the bird, so like Harry Potter staring into the Mirror of Erised, its hearts desire would stay forever just out of reach. 

I should have known better.  A few days later I caught this same birding eyeing a dead salmon in the river.  I imagined it thinking, "I'm not going to settle for any  measly little sticklebacks, I want a real meal!"

Then it went for it,

I captured the attempt on video:

The bird didn't succeed in swallowing the fish that time, but I think it may have gone back later and managed the feat.   I returned to this same area the next day and the dead salmon was gone.
Nature can be harsh metric, and most young birds succumb during their first year. Yet nature has profound wisdom too, and perhaps the life-giving salmon will bestow on these particular birds an edge in the survival sweepstakes.

As for me, what I learned from these encounters is that  "clueless" juvie birds are really not, but like all youngsters, simply trying to find their way in the world and earn their wings.