Woodpecker Wednesday - Acorn Woodpeckers 0162

            Taken at the same time (give or take 10 minutes) as what seems to be the favorite of what most visitors like, these two could be a mated pair and stayed together for quite a long time that morning.

I have posted many images of Acorn Woodpeckers in 10 years. There isn't much more information i have, but I have never gotten into one of the most unique behaviors found in only nine percent of birds worldwide, "cooperative breeding." I can never remember this rather seeming convoluted behavior, so here we go again. It's woth a read:

"Acorn woodpeckers are cooperative breeders, living and breeding in family groups of up to 15 individuals. Field studies have shown that within the same population, groups range from monogamous pairs to polygynandrous breeding collectives consisting of coalitions of up to 8 males and 4 females, along with nonbreeding "helpers at the nest" that are offspring from prior breeding events. Regardless of composition, all breeder males (who are usually brothers or fathers and their sons) compete for matings with all breeder females (who are sisters or a mother and her daughter), the latter of which lay their eggs communally in the same nest cavity. There is considerable variability within and among populations, suggesting extraordinary social plasticity. Cooperative breeding, defined as more than two birds taking care of nestlings in the nest, is a relatively rare evolutionary trait that is thought to occur in only nine percent of bird species. Most cooperative breeding species have helpers at the nest, but acorn woodpeckers are unusual in exhibiting both helping at the nest and cooperative polygamy (polygynandry). It is generally believed that limited territories are a key driver of cooperative breeding behavior in birds, and in the case of the acorn woodpecker, the availability of acorn storage granaries (see Food and feeding) is a key limited resource.

Breeding coalitions consist of up to eight cobreeding males and up to four joint-nesting females. However, most nests consist of only a single breeder female and 1 to 3 cobreeder males. Nesting groups can also contain up to ten offspring helpers. As mentioned above, the breeder males are often brothers, and the females are usually sisters. However, reproductive vacancies--formed when all the breeders of one sex die--are filled by unrelated birds from elsewhere, so Inbreeding is rare, despite the high degree of relatedness among most group members.

More peculiar still, in groups with more than one breeding female, the females put their eggs into a single nest cavity. A female usually destroys any eggs in the nest before she starts to lay. Once all the females start to lay, they stop removing eggs.Although multiple paternity and maternity are common within groups containing multiple cobreeders, no extra-group paternity has been detected."

In this photo, the female is on the left; the male on the right.

Taken in: United States / California / Rock City (show map)

Taken on: July 17, 2013

Tags:

Sets appears in: • Woodpeckers, Sapsuckers, and Flickers

Groups appears in: • Woodpeckers • Lots Of Woodpeckers more » • The Magic of Nature • Nature, wildlife, and the great outdoors • Woodpeckers of the world • Birding In The Wild • Wild Nature • Photographing Birds • Earth Images Nature Photography • Bird Portraits • Nature's Patterns • Nature For All: Flora & Fauna • Wild Birds of North America • Woodpeckers - All Woodpeckers - Only Woodpeckers • Woodpeckers of the world!! « less

Camera: Canon PowerShot SX40 HS, f/5.8, 1/640 sec, 150.5mm, ISO 200 (more info) (hide info)

Camera:	Canon PowerShot SX40 HS
Aperture:	f/5.8
Exposure Time:	0.002 sec (1/640)
Focal Length:	150.5mm
ISO:	200
Exposure Bias:	+2/3 EV
Flash:	Off, Did not fire
Exposure Mode:	Manual
Metering Mode:	Multi-segment
White Balance:	Manual
Color Space:	sRGB
Software:	ACDSee Professional 2022
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