Saturday, September 26, 2009

Pileated vs. Flicker

While sitting on the front porch enjoying the hot afternoon I began hearing the drumming of a woodpecker. It was close and echoed loudly through the wooded area that borders our property. Hollow snags are used by woodpeckers to drum allowing each repeated thud to resonate long distances. Drumming is performed for several reasons- to attract mates, to communicate with mates, and as a way of claiming territory. (Check out this really cool blog for sound recording of various woodpeckers drumming.) This area runs rampade with various types of woodpeckers (i.e. red-bellied, downy, hairy, pileated, flickers, red-headed, and sapsuckers) so drumming is a common sound. But the drumming I was hearing was really loud and the sound was trailing off at the end. I glassed the area where I thought the din was coming from and noted several old pine snags about 30-40 yards into the woods. Scanning each snag from top to bottom I eventually spotted the source of the drumming- a pileated woodpecker. This woodpecker is the largest found in the U.S. next to the supposed extinct ivorybill woodpecker. They are found all over this area and are very interesting to observe.

The pileated was perched near an entrance hole to a nest cavity that had been excavated on this particular snag. To possibly find the nest of this bird so close to camp was very exciting to say the least. Upon taking a closer look though I noticed that the entrance hole was not typical of a pileated woodpecker. Normally they excavate a hole that is oblong or rectangular in shape and this particular hole was round. Then again I can recall seeing photos of pileated cavity entrances that were round.

After a few minutes of observing I spotted the true owner of this cavity- a northern flicker. It was peering from the entrance watching the larger woodpecker as it drummed nearby. Was the pileated trying to claim this site by this drumming? They’re known to take over red-cocked woodpecker cavities, so why not a flicker cavity?

What happened next was something I had never seen. The flicker, after putting up with the seemingly endless drumming, decided to leave its cavity, which would prove a mistake, because seconds later the pileated entered it. When an invading bird does this it’s usually not a good thing. Straight away the pileated’s head appeared at the entrance with one of the flicker’s eggs in its bill. Jumping from the cavity it disappeared into the thickly wooded area with the egg in tow. I watched for quite awhile longer and only saw the flicker return.

There are several questions to consider:

1)Was the flicker using a hole previously owned by the invading pileated woodpecker? Flickers excavate their own cavities in dead trees and sometimes take advantage of previously used cavities.
2)Was the removal of the egg a territorial behavior?
3)Would the pileated be back to remove the rest of the eggs?
4)Would the flicker abandon its nest site now that it had been invaded?

I’ve check Bent’s Life Histories, SORA, and several other sources for any info on this type of behavior in pileateds and have so far found zilch. The only woodpecker I did find that exhibits this behavior is the red-headed woodpecker. If anyone has any information on this type of behavior in pileateds please let me know.

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