Palms, acorns, and woodpeckers

[bruce Steele]

There was a very tall old robusta in my front yard in SB. Woodpeckers had drilled hundreds of holes in the old attached leaf bases and constantly kept the drill holes full of acorns. My house was two stories and you could look out the windows eye level to where the woodpeckers kept up their work. The birds would move up and down the tree and turn their heads sideways to listen to the stashed acorns. The woodpeckers were farming worms in the acorns and when the worm was ready they would pull the acorns out of the hole and eat the worms. I’ve never read much about these acorn woodpeckers and why they fill palm trees with holes and acorns . Is this just a Southern Calif, habit of our woodpeckers or is this common anywhere else. 

[idontknowhatnametuse]

Never seen it happen here, woodpeckers and acorn trees are both native of my state but I've never seen the birds "farming" worms in that way, they rarely do anything to palm trees.

[Silas_Sancona]

8 minutes ago, idontknowhatnametuse said:

Never seen it happen here, woodpeckers and acorn trees are both native of my state but I've never seen the birds "farming" worms in that way, they rarely do anything to palm trees.

Look up: Acorn Wookpecker, Melanerpes formicivorus.  Very common in CA.. Common in the foothills here.  One of my favorite Woodpecker species. Had one that would raid a plate of peanuts i'd put out for Scrub Jays..

Interesting that they'd use palm leaf bases for storing of Acorns but, is a softer material to punch holes in, so it makes sense they'd figure out that niche. 

iNat link:  https://www.inaturalist.org/taxa/18209-Melanerpes-formicivorus
 

[bruce Steele]

Acorns are seasonal and the worm will metamorphose into a moth so there is only so much time  the woodpeckers have to harvest their efforts. I would bet the nesting period is timed such that the babies in their nests and the ripening worm garden time together.  I used to throw walnuts from my balcony out onto the street for some local crows. I realized after awhile that the acorn woodpeckers were cleaning up what the crows left behind and as a result were being hit by cars. Crows are smart and they know our cars, the woodpeckers not so much. So I quit feeding the crows. 

 

[Silas_Sancona]

5 minutes ago, bruce Steele said:

Acorns are seasonal and the worm will metamorphose into a moth so there is only so much time  the woodpeckers have to harvest their efforts. I would bet the nesting period is timed such that the babies in their nests and the ripening worm garden time together.  I used to throw walnuts from my balcony out onto the street for some local crows. I realized after awhile that the acorn woodpeckers were cleaning up what the crows left behind and as a result were being hit by cars. Crows are smart and they know our cars, the woodpeckers not so much. So I quit feeding the crows. 

 

I've witnessed them storeing acorns in say October from some Valley, Blue, and Coast Live Oak that grew across from where i lived at one time in San Jose  only to periodically raid their " pantry "  ..a favored utility pole in a neighbor's yard,   at various times thru the winter months. 

Believe that yes, in spring when they are nesting, their diet switches predominantly to insects..  ....Was when the neighborhood kids would abandon their favored pantry for a few months, lol.

[bruce Steele]

The grubs/ worms turn into weevils and not moths, my mistake. The preferred storage trees for the acorn woodpeckers are called granaries. I would bet that in Baja the acorn woodpeckers use Robusta as granary trees but maybe it is only where the Washies get their leaves trimmed that they get good granaries out of  Robusta. But the woodpeckers and the Robusta share the same native habitat and Washies get trimmed in Mexico too. 

[Silas_Sancona]

45 minutes ago, bruce Steele said:

The grubs/ worms turn into weevils and not moths, my mistake. The preferred storage trees for the acorn woodpeckers are called granaries. I would bet that in Baja the acorn woodpeckers use Robusta as granary trees but maybe it is only where the Washies get their leaves trimmed that they get good granaries out of  Robusta. But the woodpeckers and the Robusta share the same native habitat and Washies get trimmed in Mexico too. 

Definitely possible, ..if or when they aren't using live or the dead snags of the Quercus / other dicot tree sps down there. 

While they rarely venture into the valley up here,  i have seen ( and heard ) them when roaming various parts of the valley floor in Tucson, ..areas closer to the Catalinas / Rincons, or the Santa Cruz River / other major area washes w/ proper vegetation corridors esp.   but didn't notice any activity in any of the palms at Agua Caliente, or on older Sabal or Brahea  sps growing in gardens like Tohono Chul Park 

..Or even up at Boyce Thompson for that matter,  which sits right below Apache Leap / Oak Flat,  and in a sorta -basin,  tucked between the South / S.E. facing flank of the Superstitions, and mountains that make up the Picket Post / White Canyon Wilderness area south of Boyce / the U.S. 60  ..interesting.. 🤔

Instead, it is usually Oaks, Pines / larger Pinyon, ..and the occasional AZ Cypress ( both forms ) where i'd noted granaries at places like Oak Flat or Madera Canyon -where these guys spend most of their time.  Imagine i'll note similar activity in the same tree types when exploring other areas, esp. in the southern part of the state where a majority of our Quercus sps grow.  Mexican - origin species esp..

That said, because the Escarpment form of Live Oak ( Quercus fusiformis )  is being planted more in the valley ( and around Tucson proper ),  in time,  i could see these ..and maybe even our local form of Scrub Jay make winter season trips into neighborhoods with larger Live Oaks that are producing large Acorn crops. See Curve - billed Thrashers toss Acorns around beneath neighborhood specimens so often atm.  Grackles also occasionally pick up  ( and drop ) acorns off them as well.

Love Birds and the occasional Ladder Back ( Woodpecker ) aside, for now at least,  it's the Gila Woodpeckers  you'll see poking around palm trunks here in town..

In FL, it was Pileated W.P's i'd see eyeballing me from this or that side of palm trunks.  Great looking bird.