On The Cusp of Summer: Nestlings and Fledglings

Technically, according to the calendar, it's still spring.  Technically.  However, as temperatures push toward 100 degrees Fahrenheit here in California's Great Central Valley, it is rapidly beginning to feel much more like summer than spring!

In the bird world, spring migration has pretty nearly wrapped up for the season, as birds settle down on their breeding territories.  Many of our local resident breeders have been hard at work raising their young for a couple of months now, many of whom have already fledged their first brood this season.  

Across the wetlands, riparian woodlands and grasslands, even throughout urban and suburban neighborhoods, the air is full of singing males defending their territory and the sound of hatchlings and fledglings begging their parents for food.  Yes, the nesting season is well underway indeed!

Singing Marsh Wren:
because nobody defends their territory quite like these little mites of the marshes!

We've been fortunate enough to be able to spend time out with the birds at least once every week for the past few months, watching as the seasonal changes steal across Valley landscapes.  

In the wetland portions of the San Joaquin River and San Luis National Wildlife Refuges, Marsh Wrens, Common Yellowthroats and Song Sparrows are singing their hearts out in defense of their breeding territories.  While the nests of songbirds are usually extremely well-hidden, the presence of a singing male often indicates that a nest is probably somewhere nearby.  Adult birds carrying food in their bills is an even better clue to the presence of an active nest in the vicinity.  

Whatever this Song Sparrow, pictured below, has in its bill is not for its own consumption: this tasty morsel is destined to fill the tiny mouth of a young nestling concealed somewhere nearby.

Adult Song Sparrow carrying food

In tangled thickets of riparian vegetation, oak woodlands and chaparral, listen for the begging calls of young birds, recently fledged from their nests.  Look closely for small birds, like House Wrens, Western Bluebirds, Bushtits, and Oak Titmice, busily going about their domestic duties.  

Because nests are like bullseye targets for a wide and varied array of predators, songbird young develop remarkably fast.  While a nest may seem like a snug, safe place to be, the cruel reality of nature is that they are often extremely perilous places.  In addition to attracting the attention of predators, nests can also become fouled with feces and infested with pests.  The faster young birds develop and leave the nest, the better.  

During the fledgling stage, after young birds leave the confines of the nest but before they are fully independent, young songbirds spend time out of the nest, concealed safely in vegetation while their parents spend their days foraging for food to feed their growing brood.  Fully feathered fledglings are often more conspicuous than younger nestlings, which are still secreted away in their nests, and offer the observer delightful opportunities to enjoy wild bird behavior that ranges from the tender to the ridiculous!  Youngsters often sit quietly in a relatively hidden location, until their parents return with food, which signals the young birds to scream and fuss loudly, waving their wee little wings frantically and gaping wide, until they receive their share of the meal.  It's these sounds that often give away their presence to quietly observant birders!

While birding at the San Joaquin River NWR, shortly after a delightful encounter with five recently fledged Oak Titmice and their two rather frantic parents, I came across a young California Thrasher and watched with a smile as its parent brought it food.  

A California Thrasher fledgling.  Notice that this young bird still shows a light-colored gape (the corners of its mouth), retained from its days as a newly-hatched nestling.  Its bill and tail are also shorter than they would be on an adult thrasher, and its feathers have a soft, downy look to them.

The youngster (on the right) is begging loudly for the morsel of food carried by its parent!

Having been fed, the fledgling is satisfied.  For now.

  

In grassland habitat with scattered trees, be on the lookout for Western Kingbirds.  Like all flycatchers, kingbirds perch in the open and hunt flying insects.  They build their nests in the crotch of a tree or shrub (or in some cases, man-made structures) and in our area, they seem to favor oaks and cottonwoods.

Adult Western Kingbird

A precious trio of Western Kingbird fledglings.  

Another type of flycatcher, Black Phoebes are common in a number of California's habitats.  I recently came across these delightfully soft-looking phoebe fledglings perched quietly on a branch above a small creek.  Notice their tan wingbars, which will fade as they reach adulthood.

Black Phoebe fledglings.

I have also had the pleasure of watching a couple of raptor nests this spring.  The first, a Great Horned Owl nest, has been active since late winter.  Great Horned Owls don't build their own nests, but refurbish and reuse the abandoned nests of hawks and large corvids. 

Great Horned Owl, on her nest (March 31).  There is a young owlet hidden in there!

Great Horned Owl and owlet (April 14).  My guess is that this owlet is around 4 or 5 weeks old.  At around 5 weeks, owlets begin "branching," or climbing around on branches outside their nest.

The owlet here is probably around 6 or 7 weeks old. (April 28)  Young owls begin to fly around 9 or 10 weeks, but they will be 6 months old before their adult feathers have fully grown in.

A Red-tailed Hawk nest, found high in a cottonwood tree, has been active since April.  It has been fun to watch the development of these little guys, from fluffy little dinosaurs to juvenile birds capable of flight!

Fluffy white Red-tailed Hawk nestlings, probably around 2 or 3 weeks old (April 28)

One of the nestlings, showing more color in its feathers, probably around 4 or 5 weeks old (May 12).  Clearly, I have been spotted!  Young hawks are very inquisitive.

On May 26, both fledgling hawks were out of the nest, hanging out on branches nearby, working on developing their classic Red-tailed scream, and taking short experimental flights.  At least one parent was still in the vicinity.  Young Red-tailed Hawks leave the nest when they are around 6 or 7 weeks old.  It will take them another couple of weeks to become strong flyers, however, and young birds remain dependent on their parents for several more weeks after that.

 

But the breeding season is really only just beginning!  In my own backyard, I have been privy to the charming antics of young Lesser Goldfinches, following their parents and begging for food; House Finch fledglings with fluffy down still sticking up in tufts from their little heads; and recently-fledged California Scrub-jays, enthusiastically exploring every corner of the garden.  (The curious and highly intelligent jays are extremely entertaining to watch as they acquaint themselves with their new world!)  

As spring fades into summer, keep an eye out for signs of breeding birds in your area: watch for nest building activity, as birds carry twigs and other nesting material, or examine potential nest cavities; listen for males singing in defense of their territories, and the incessant sound of young nestlings and fledglings begging for food; and watch closely as young birds leave the nest and venture out into the world on wobbly wings!