Double Crested Cormorants in Springtime, their gular pouches (sacs) are hidden
Even when engaged in fighting, DCCOs often do not display their gular sacs.
However, here we see a DCCO with its gular sac extended, warning a
Neotropic Cormorant to move on.
In this expanded image, notice the DCCO with its YELLOW/ORANGE gular sac signaling, 'get lost' to the NECO
Turnabout is fair play! On another day, a NECO (Adult/breeding plumage) attempts to steal a fish from a DCCO, with the DCCO flourishing its gular sac big time!
Here is another view of the action as the NECO becomes the marauder!
Finally the NECO takes flight for one last attempt to grab the fish from the DCCO.
Now we've seen the gular sac on a DCCO, let's take a look at what the NECO's expanded gular sac looks like! Below are 2 NECOs, with gular sacs hidden.
This group of NECOs vary in age. All of them possess PINK gular sacs as seen at the left.
The NECO on the right displays its PINK GULAR SAC during a chaotic moment.
(Note: Typically in NECOs' Social Signaling, I've seen extended gular sacs simultaneously
with their mouths agape!)
Two perched NECOs, signaling for a 3rd in the water to depart, with visual and vocal resistance from the 3rd NECO. Note the PINK gular sacs!
On another occasion a lone NECO frets when a female Mallard swims by...
The female Mallard has ducklings, thus tries to defend herself.
The Mallard 'holds her own' with the fierce NECO!
Things get heated up and the Mallard and babies scatter!
The NECO continues to be agitated, even after the intruders are gone. Note the PINK
Here, I'm looking over the 'shoulder' of one NECO, doing battle with another! Note the PINK
Here we see 3 Adult (breeding plumage) NECOs hassling over real estate.
The 2 perched NECOs succeed in warding off the third individual, all displaying their unique PINK gular sacs.
The panels below summarize my hypothesis:
3 NECOs of varying ages...
From left to right:
L) Juvenile NECO that could be confused with a Juvenile DCCO!
Notice the Yellow Lores on this bird!
C) Adult NECO.. No yellow in the Lores.
R) Adult NECO, breeding plumage
(NOTE: If the Juvenile is a DCCO, it will display a YELLOW/ORANGE gular sac.
If the Juvenile is a Neotropic Cormorant it will display a PINK sac.)
This additional photo shows 2 of the same birds again.
NOTICE, THE JUVENILE LOOKS SOMEWHAT LIKE A DCCO!
HERE ARE THE SAME 3 BIRDS, DISPLAYING THEIR GULAR SACS.
ALL 3 BIRDS MANIFEST PINK GULAR SACS!!
THE JUVENILE IS A NECO!
IN SUMMARY, WHEN FIELD GUIDES DESCRIBE NEOTROPIC CORMORANTS GOING FORWARD,
ADDITIONAL INFORMATION MIGHT BE INCLUDED (see pink statement below):
"They can be distinguished from other Cormorants by a white outline around the gular pouch and base of the bill. The gular pouch appears triangular rather than rounded as in Double Crested Cormorants.
IF THE GULAR SAC IS EXTENDED IT WILL BE OBSERVED TO BE PINK, WHICH IS A UNIQUE CHARACTERISTIC WITHIN THE SPECIES."
Only one lone Adult NECO appeared at my study site, Mill Race Pond, Salt Lake Valley,
in May, 2011. (Sight Record)
However, it did provide me this photo opportunity while stowing away
a sizeable Panfish.
Again, notice the pink gular sac!
This concludes section 1) "Social Signaling"
Section 2) "Courtship" can be found here.
Section 3) "Gular Flutter" can be found here.
Richard B. Young