[CT Birds] A question on cryptic plumage.
kmueller at ntplx.net
kmueller at ntplx.net
Wed Feb 27 11:39:39 EST 2013
That's a good topic Paul. This is better answered by an Ornithologist,
but let me add a short narrative based only on my experiences and
thoughts. Although a Downy Woodpecker is clearly a bird with what we
perceive as a strikingly obvious plumage pattern. But maybe in some
instances though, it is very camouflaged. If you see this bird walking
up a tree trunk or on your bird feeder in the open or at eye level,
the pied plumage does stand out to us, but what about a predatory
bird? Even in the open, the random pied patterns of the Woodpecker
does create a certain amount of confusion, probably enough to offer a
window of escape. If you look at this bird in a different location and
angle, say looking up into the tree branches. The black barring and
white spotting will replicate the interplay of light and branch
patterns making the bird virtually disappear.
This sighting Jen and I experienced many years ago, opened my eyes to
how a seemingly striking and brightly colored bird can escape
detection from a predator. We were in Costa Rica floating down the Rio
Sarapiqui on the Caribbean slope. I was studying Keel-billed Toucans
and this area was a good location for them. The boat ride gave us a
very private and intimate platform to study the birds in areas where
the birds were undisturbed. Everyone knows the bright colors and
plumage of a Keel-billed Toucan: bright green and yellow/green bill
with an orange patch on the sides of the upper mandible and bright red
tip. The plumage is basically black with magenta highlights on the
head, bright yellow cheeks and chest (bib), white upper tail coverts
and a scarlet red crissum.
We located a few small flocks of the birds (approx 30 birds total)
along the river. They were roosting in the open branches cluttered
with epiphytes hanging over the river. Some were enjoying the morning
sun, others were partially in the shade. Their bright colors stood out
like a neon light in the sun.
When we got closer, they all scattered into the deeper branches and
foliage of the trees, but still at eye level. We pulled the boat
closer to the overhanging trees, and although we could here then
calling, we couldn't see one of them! The guide kept telling me that
they were right in front of us at a few meters, but we still couldn't
see them. At one point the guide (who was smiling a bit) stood behind
me and ran his outstretched arm right in front of me pointing to a
small cluster of birds. We still couldn't see them. We could hear them
and they sounded like they were a few feet in front of us, but no
luck. Finally one bird moved an it came into focus for us. It was
amazing how such a brightly colored bird can be so difficult to find
just because of a little shade.
In the rainforest, there is all kind of shapes and colors being
augmented by the dabbled light that is allowed to squeeze through the
canopy. Seemingly brightly colored Green leaves, yellow leaves, red
flowers and bromileads, etc, can range in colors from their enhanced
bright shades of color to the severely diffused and darkened values of
the colors being altered by the shade. To add to the "confusion" if
you look up, spots of white light peek through the open areas of the
canopy adding more details to the already confused array of colors,
shades, shapes and illusion. To evaluate the Toucan as it sits in the
shadows. The colors of the plumage and bill are also diffused by the
shade of the recesses of the trees. The bright bills look exactly like
the dark green shades (and shapes) of the darker leaves. The dark
yellow bib matches the dying and dead leaf colors and patterns that
are mixed in with the values of green leaf and vegetation colors. The
darkened red crissum and bill colors appear brown matching the colors
of the branches and bark of the tree, and the the white spot of the
upper tail coverts...just another light spot poking through the canopy.
So if a brightly colored Keel-billed Toucan can vurtually disappear in
the lush and color intense rainforest, the Downy Woodpecker has a much
easier job. Our lessons continued on the river with Orange-chinned
Parakeets. When these large flocks retreated into the shadows,
honestly, I am still looking for them! This will take some time!
Mother nature is so talented!!
Quoting Carrier Graphics <carriergraphics at sbcglobal.net>:
> A question on cryptic plumage.
> While looking out at the feeder birds this morning, I saw a neat and
> trim male
> Downy woodpecker. Then a question came to mind.
> Why has evolution given this bird such a contrasting coloration? There is no
> better coloration to be noticed than Black against white. A downey
> is certainly
> not the best cryptic colored bird out there to deter predation by hawks, and
> certainly not the best in flight to avoid predator attacks, (slow, undulating
> flight) so whats up with that?
> Hawks it is know have less color vision with the added benefit of better
> perception in movement and contrast – so one would think the Downey
> is a prime
> prey species for any hawk. Contrasting B&W plumage, with a not so elusive
> flight. So why are their so many Downeys about? Logic would tell us
> they should
> have been eliminated a long time ago... Any thoughts out there?
> Paul Carrier - Harwinton
> This list is provided by the Connecticut Ornithological Association
> (COA) for the discussion of birds and birding in Connecticut.
> For subscription information visit
More information about the CTBirds