Bushtit crazy time

It's that time of year.   Nests are mostly complete.  Some birds are egg-laying and incubating.  But it's not nearly that simple.  It's time for the friendly little bushtit to become not so friendly to their flock mates.

Today I saw a couple of good examples of bushtits mis-behaving:

The first was at a lovely nest over-hanging a creek.  It was finished quite some time ago, being built by an unbanded pair.  Soon after the nest was finished we began to see chases around the nest when we visited.  Apparently someone (we couldn't see who!) was interloping and perhaps trying to take over the nest.  That happens.  Without color-banded birds in that area, I can't be certain what the outcome was.

Today I was watching that nest again.  First an unbanded male showed up with nothing in his beak.  This was suspicious because both male and female bushtits continue to carry nesting material into the nest after it is finished and through incubation.  Soon after, an unbanded female arrived and went right to the nest.  Also with nothing.  Instead of going into the nest as the "owner" would, she peered in and then hopped about the nest, cocking her head as if to inspect the real estate.  The entire time the unbanded male stayed in a branch above as if keeping a look-out.

They left quietly to the north after a few minutes, neither one ever entering the nest.  Immediately from the direction they took and nearby I heard the sound of chasing bushtits (loud spits!).  I couldn't see what was happening, but I could hear it.   Then suddenly, a pair shot past me heading south, followed by a lone male.  It must have been the presumed nest-owner chasing off the interlopers.

I can't wait to have these birds banded!  Then things will become much clearer as they always do.

So why the fuss from the owner (assuming that what was happening?).  Well, sometimes owners are booted from their nests.  And sometimes neighboring females secretly lay an egg in a nearby nest -- usually while her mate stands guard.

So there is good reason for neighbors to keep neighbors away!

The second instance was a banded male (RCRX), nowhere near his own nest, chasing an unbanded male near that male's nest.  This went on for quite awhile while a female entered the nest several times with feathers.  What RCRX was doing is anybody's guess.   But last year another male (RXRG) did take over a neighboring nest while his own nest was being incubated by the female alone (not the usual arrangement).  After taking the other nest over and ensuring there were eggs present and being incubated, RXRG returned to his first nest to help feed the kids, leaving the female at the second nest to raise her kids alone.

There's a quite a bit more to THAT story.  It's very complicated.  But I'll save it for another day.