Birdhouses in the Vineyard, 2021

Bluebird mother sitting on her eggs.

In 2020 we put up 33 birdhouses in our vineyards to attract bluebirds and other species in need of nesting sites.  They also help the vineyards by feeding on insects.  102 chicks fledged over that summer.  Check out my blog post last year for the backstory and how we used mostly recycled wood to build the boxes.  Birdhouses are easy to make and maintain, and we encourage you to make your own to help out your local bird population.  A great resource can be found at the Cornell Lab of Ornithology website.

This year we nearly quadrupled the number of birdhouses to 121, and 554 chicks successfully fledged the nests! 

Total fledged:
336 bluebirds
172 tree swallows
29 house sparrows
11 ash throated flycatchers
6 white breasted nuthatches

This is more than quadruple the number of fledglings from 2020.  Last year we learned that the birds in general prefer boxes hung on metal stakes in the open vineyards over boxes placed in trees.  If a box was vacant, more often than not it was in a tree.  The birds know what we observed: boxes in trees had a higher rate of disturbed nests.  Racoons and snakes can easily climb trees and reach in for the chicks, but the metal stakes are nearly impossible to climb for predators.  Also, mice like to turn birdhouses into their private apartments.  Even after eviction, birds seem to avoid the boxes.  No mouse squatters appeared in the birdhouses hung high on metal poles.  Of course not all birdhouses in trees had problems and birds will use whatever suitable hole in a tree they can find, but in general the rate of troubled nests was much higher in trees.

Of the 121 birdhouses, 26 remained unoccupied throughout the breeding season, usually those on trees or were in the shade for most of the day.  Of the 95 boxes that were taken up by the birds, 36 of them were used twice!  After a pair finished raising their brood and moved on, another pair sometimes moved in.  That makes 131 successful nesting pairs using only 121 boxes.

As spring turned to summer, the number of nesting birds dropped off and the number of chicks per family declined as well.  In spring when insects were plentiful, bluebirds and tree swallows averaged 5 or 6 chicks in a box.  Later in the summer the average dropped to 3 or 4.  Nature can be brutal, as many chicks don't make it.  A brood of 6 chicks might decline to 3 later in the summer, probably because of fewer insects for the parents to catch.  Inexplicably, around three nests were completely abandoned, each with 5 or 6 fledglings, the parents likely victims of predation.

I checked all 121 birdhouses about every 10 days, often with the help of my 10 year-old sun Julian and 6 year-old daughter Sofia, counting the eggs, chicks, and noting if they had fledged.  Some online sources recommend checking every 5 days, but it takes a lot of time to go from box to box, using a ladder or climbing onto the back of a pickup to reach the boxes.  Each box has a door for inspection and cleaning.  After a pair of birds raise and fledge their babies, the nest gets cleaned out.  If it’s not too late in the season, another pair of birds will use the same box.  When cleaning out a bird box, be sure to wear a mask and take note of which way the wind is blowing.  The chicks leave a lot very dusty bird waste behind, that you don’t want to breathe.

The boxes set up last year were left out in the vineyards over the winter.  They got noticeably weathered by the cycles of rain and sun, cold and heat, after just one season.  So this year most were removed at the end of summer and placed in dry storage for the winter.  They’ll be put out again early next spring.  We hope this will add several years to the life of these wooden birdhouses.  At the ends of the rows of most of our vineyards are metal pipes used as anchors for the trellises.  The metal stakes, with the birdhouses attached on top, can easily slip into these thick pipes, making for easy installation and removal.  Removing them at the end of summer also helps the harvest crew, as they otherwise would have to get them out of the way for the harvest machines.

We look forward to spring 2022 for another season of raising bluebird chicks in the vineyards!

Stack of birdhouses ready to be attached to the metal stakes.

Birdhouse at the end of a row of grapes.  The metal stake slips right into the anchor post.

Birdhouse squatters soon to be sent on their way!

A lovely spring day for a birdhouse in the vineyard.

Bluebird eggs.

Ash throated flycatcher chicks!

Birdhouses in the Vineyards

Bluebird hatchlings at a Frey organic vineyard, Redwood Valley, California.

In the spring of 2020 we placed 33 birdhouses in our vineyards to help bluebirds and other species that are in need of good nesting sites.  A total of 102 chicks were raised and fully fledged!  The birdhouses were made mostly with recycled wood from the construction of our new winery.  The organic vineyards in the spring and early summer provide lots of open space for the breeding pairs to hunt for insects.  The reduced number of insects is also good for the grapevines.

The depletion of woodlands in the U.S. has made life difficult for many bird species, especially for birds that nest only in tree holes.  Native birds also have to compete with larger and more aggressive invasive species for prime nesting sites.  For example, the larger non-native European starling will kick out birds from a site to take it over for their own brood.  The entrance hole for the birdhouses we made are just wide enough for native species to squeeze through, but too tight for starlings.

We put up the birdhouses in trees next to the vineyards and on metal stakes at the end of vineyard rows.  Each birdhouse was inspected weekly.  It’s important to monitor the nests and to clean out the straw and detritus after chicks have fully fledged so another breeding pair can move in, even within the same breeding season.  We observed 4 birdhouses that were used twice.  The birds prefer the boxes to be totally empty, no leftover nesting material inside when scouting for a site.  Also, parents often abandon a nest before finishing it, and on occasion even a finished nest with eggs might be abandoned.  Each birdhouse had a number written on it and a spreadsheet app was used to help keep track of so many nests!

Ten of the 33 birdhouses we set up were not used at all by any birds.  Maybe these nests didn’t have enough sunlight in the morning, or they were too close to other nests.  Several online sources say it’s best to separate birdhouses by 300 or 400 feet, as members of the same species are territorial.  But it’s possible two different species will get along fine when nesting next to each other as each might exploit different ecological niches over the same plot of land.

For the remaining 23 birdhouses, 102 chicks fully fledged!  Four species took advantage of the boxes, mostly bluebirds and tree swallows.  In total there were 51 western bluebird chicks, 31 tree swallows, 11 titmice, and 9 ash-throated flycatchers.  We hope to add even more birdhouses for next spring!

Birdhouses are easy to make and maintain, and we encourage you to make your own to help out your local bird population.  A great resource can be found at the Cornell Lab of Ornithology website.
 

Birdhouses made from wood recycled from Frey Vineyards' new winery construction.

The birdhouses hung at the ends of vineyard rows were very popular with Bluebirds and Tree Swallows.  The wobbly but secure high metal stakes are good protection against racoons, snakes and other predators.

Each birdhouse has a door for easy monitoring.  Bluebird and Tree Swallows will not abandon the nest following a quick inspection.  They will divebomb the intruder instead!

A bluebird enters a birdhouse next to organic vineyards. 

A pair of tree swallows surveys the vineyard.

Bluebird eggs!

A bluebird dad delivers an insect to its ever-hungry brood.

Beautiful ash-throated flycatcher eggs.

Bluebird younglings ready to fly the nest!

 

Snack delivery by an ash-throated flycatcher.