Building a Bird Island


Cormorant on 2' x 2' unit

Machado Lake in KMHRP used to have many silt islands scattered along its course. These islands were used by birds for roosting, resting, and even nesting. The historical record indicates several species used to nest on them such as Avocet, Black-necked Stilt, and Snowy Plover (now endangered), and other species that required a "safe haven" from people and predators.

These islands were dredged at various times as part of "management," but with no consideration for the wildlife using them. That such "safe havens" are important is illustrated by the fact that anything floating in the lake is used as a perch now. There is no place along lake shore that is dog and people free for birds to rest undisturbed, much less nest. Like you and I, birds need to rest undisturbed as much as we need to eat.


Least Terns using rest stop

One day I decided we had to do something about this. I was tired of seeing birds fight to roost on the one floating board in the lake. Though at the Park Advisory Board meetings I'd urged, asked for, begged, and pleaded to reconstruct islands for years, it was clear that was not going to happen soon. Amazing we can remove the habitat without mitigation, and it will take an 'act of congress' and millions to recreate what we destroyed, yet again.


Juvenile Least Terns follow their parents
to the park to learn how to fish.
Note the band on the bird's leg.

So, I decided to try to make an island. Requirements were that they be temporary and moveable, and not deteriorate, or leach toxins into the environment. I build aquaria filtration systems with PVC and "eggcrate" (the fluorescent light plastic grids) and thought I might be able to fashion something acceptable to the birds with it.

In short order a couple of Mitch's (patent pending- just kidding :):)) bird islands were engineered, and assembled, and arrangements made to "install and deploy" them in the lake.

The second day they were there, birds were on them! I started keeping a list of which species I'd seen on them, and was amazed to see everything using them! The list now has nearly a couple dozen species on it.


Least Tern adult with juveniles

The greatest thrill was counting 13 endangered LEAST TERNS resting on two platforms in 2002. They were mostly juveniles from the local colony at Terminal Island. THEY JUST NEEDED A PLACE TO SIT AND REST UNDISTURBED! Even a Pied-billed Grebe pair built a "platform" nest!


Pied-billed Grebe platform nest

At the Park Advisory Board we sometimes have Scouts in need of an Eagle Scout project, so we offered this up, and two scouts built several and installed them. They were all getting used. At one point in 2002 about a dozen were in the lake, with 9 at once being used by birds. Unfortunately in the huge storms of winter 02-03 we lost a bunch of them, and now are in need of replacing them.

Since some of my handwritten notes, drawings and instructions were hard to follow (surprised?), here we present a different set of confusing instructions, illustrated with photographs to show how to make them. I've heard some places used tires as floating bird roosts successfully. My technique is using new materials as opposed to "recycling," but I didn't have a stack of tires handy, just a bunch of PVC, eggcrate, and glue.

There are countless lakes and ponds that would probably benefit from these sorts of safe roosts. Especially in city parks where shores are dredged, and there is often a lack of habitat governing what can roost, rest, or nest at a given site.


A Gaggle of Gadwall, gadding about no doubt, on 2'x 2' unit

The list of birds I've recorded on these artificial roosting islands includes: Pied-billed Grebe, Eared Grebe, Double-crested Cormorant, Great Blue Heron, Great and Snowy Egret, Gadwall, Am. Wigeon, Mallard, Redhead, Ring-necked Duck, Am. Coot, Black-necked Stilt, Spotted Sandpiper, several species of Gulls, and Forster's and Least Terns!

Click here for instructions on How to Build a Bird Island