Arizona 1987: Dad as a decoy

[BOOK EXCERPT]

Against all odds,  PPLX and RYLX have recaptured their nest from the interlopers [future Blog entry on this!] and now have young nestlings in the nest they fought so hard for.  The nest itself, built while the oak was simultaneously shedding its old leaves and sending out catkins has proved to be elderly and now has leafed out only sparsely.  The result is that the nest is still quite exposed.  To make matters worse, the area is particularly ripe with jays who would make fast work of the nest and its contents if they were to find it.  In fact, I am quite surprised it has made it this far. 

On 11 April 1987, I arrive alone to do a routine feeding nestwatch.  I set up camp far enough from the nest to be inconspicuous to bushtits and jays alike:  shortened chair in a nice, shady spot, telescope set where I can use it easily, binocs for other observations, watch, and notebook with rapidograph ready for taking notes.   I worry less about disturbing the bushtits as they really don’t seem to care about me at all.  I could probably sit IN the nest tree and they’d just go about their business.  But I don’t want the Mexican Jays cuing in on the nest because of me.  I sometimes get the feeling they are secretly looking over my shoulder, thinking, in a sentient corvid kind of way “hmmmm….what’s she watching?  Oh look, a juicy little bushtit nest!”  I have no evidence they are doing this, but I want to take no chances.  Jay predation is high enough without my help.  

So I settle in for a very easy and pleasant nestwatch; given the openness of the nest I should have no trouble identifying the birds.  Sure enough, PPLX and RYLX are actively feeding about every 10-20 minutes, coming in with noisy spits and food, disappearing into the nest to deposit it into hungry baby bushtit mouths (as I can only imagine given that the nest is entirely enclosed), and then taking off together to find more food for the growing kids.  But I don’t hear the nestlings begging before the adults arrive, so they must be very young.

Then tragedy strikes…or so I think at first.  A Mexican Jay is in a pine tree near the nest and watches as the parents noisily arrive, feed the kids, and then together take off for more food. When the coast is clear and all is quiet, the jay cocks its head and slowly hops, branch by branch, to the bottom of the pine and then, in a single quiet swoop, launches and lands in the nest tree only 3 feet from the nest, eyes ominously glued on the nest itself.  Lunch.

I am paralyzed.  Do I interfere?  Do I stand and throw rocks and scream, as I so badly want to?  Or do I be the good, impartial scientist and let nature take its course?  There is a part of me that wants to actually see this, to see jay predation in action.  I never have.  I’ve only seen its sad conclusion:  the torn nest, the scattered feathers, and the silence of the empty nest.   And sometimes the confused parents spitting about the old nest, clearly wondering what has happened while they were happily collecting food for the nestlings that are no longer there.   

While I’m in this state of indecision, both parents return to the nest, and assessing the dire circumstances, begin mobbing the jay as best a bushtit can.  Without dropping their loads of caterpillars and whatnot, they somehow manage to spit madly at the intruder, diving at its head like a swarm of angry mosquitoes.  But sadly the jay seems unperturbed by the tiny assailants (who would be?) and creeps closer to the nest, clearly intent on an easy meal.  All seems lost.

But then something truly amazing happens.  As a last ditch effort, the male drops his load of caterpillars and perches next to the jay and opposite the nest.  He begins to utter a sound I have never heard from an adult bushtit:  the calls of a begging nestling.  Immediately, the jay swings its head away from the nest and toward the male, who is now begging loudly and fluttering his wings.  As soon as the jay’s attention is on him, PPLX hops to the top of the tree. The jay follows. Then into the pine.  The jay still follows.  Then they disappear.  Remarkably, the male has successfully used himself as a decoy to save the nest.  How smart and brave for such a little bird.  

I stay longer than I had planned to see what will happen and twenty minutes later both parents are nonchalantly feeding at the nest and the jay is nowhere to be seen.  Still, I think as I pack up to leave, this nest is doomed.  The jay clearly knows the nest is there.  And, as the nestlings get bigger and louder, they will become even more conspicuous.  Doomed.  Absolutely.  No doubt about it.  

But bushtits always have a way of surprising me.  In spite of high predation rates all over the study area, and in spite of the jays supposedly knowing where this nest is, the nest fledges successfully 10 days later, right on time.  And, even more surprising, the parents are back for yet another clutch just one week later.  

So much for corvid intelligence.  

Bushtits 1: jays zero.