Pigeons Nesting Under Solar Panels in Montana

Why do pigeons like the gap under an array?

It matches what pigeons look for. The Montana Field Guide says rock pigeons roost and nest in crevices and are found chiefly in cities and towns or at farms with livestock. The Internet Center for Wildlife Damage Management describes them as highly dependent on people for roosting, loafing and nesting sites, using lofts, steeples, attics and architectural features wherever openings allow.

A racked array supplies exactly that: a low, sheltered cavity with a solid lid and open sides, warmed by the roof below. The U.S. Department of Energy's operations and maintenance guidance for solar, prepared with the National Renewable Energy Laboratory, treats bird populations as a standard environmental condition for a system and recommends designing arrays to reduce the open gaps between panels where birds can build nests.

Are pigeons protected in Montana?

No. Montana Fish, Wildlife & Parks states that pigeons are not a native wildlife species and are not protected in Montana, and that their nests and eggs may be destroyed. The rock pigeon is also on the U.S. Fish and Wildlife Service's published list of species the Migratory Bird Treaty Act does not apply to. A pigeon nest under a panel can lawfully be cleared at any time of year.

That is not true of every bird on a roof. Starlings and house sparrows are also unprotected according to FWP and extension sources, but native birds sometimes nest in the same sheltered spots, and an occupied nest of a native species has to be left until the young fledge. Identify the bird first. Our guides to pigeons on Montana buildings and Montana nest removal law explain the distinction.

What mess and damage should you expect?

Pigeons do not stop at one nest. The wildlife damage center reports that a pair raises five to six broods a year, mostly in spring and summer, and that more eggs are laid before the first young leave the nest. Their nests are crude platforms of sticks, twigs and grasses, and under an array the material piles up across the roof where you cannot see it.

The droppings are the larger issue. The same source says pigeon droppings are acidic and can deface and accelerate deterioration of building materials, and that accumulated droppings can plug roof gutters and cause water damage. Below a solar array, the first signs are usually white streaking down the shingles and fascia, nesting debris and feathers washing into the gutter, and noise at first light. FWP adds that pigeon droppings damage vehicle paint and kill ornamental plants and grass, which matters if the array is over the driveway or a planting bed.

Do nests and droppings affect the wiring or the output?

Here the evidence is thinner than the marketing. The Department of Energy guidance lists bird populations among the conditions that affect soiling and says to adapt the cleaning schedule to bird season. It cites measurements of cleaning improving output by roughly 6 to 7 percent, a figure for dirt in general, not for pigeons. Droppings on the glass are soiling like any other.

We looked for a government or university source that documents birds damaging the wiring under residential panels and did not find one. Installers and guard manufacturers commonly describe debris packed around cables and connectors as a hazard, and that is plausible, but we are not going to repeat a claim we could not verify. Whether nesting material around the wiring on your particular system is a concern is a question for the installer or a qualified solar electrician, who can inspect it properly.

What is a mesh skirt or critter guard?

It is exclusion applied to an array. The Department of Energy guidance describes it as bird netting that seals the areas under the panels with a wire or plastic mesh that clips directly to the solar panels and goes down to the roof completely around the array. Done properly it closes every side, including the top edge and the gaps at rails and conduit, since pigeons will find the one bay left open.

The same guidance lists two companion measures: bird spikes along the top edge of the array to prevent roosting, and array design that leaves fewer gaps. It also lists plastic owls and falcons as a scare measure. On that point the wildlife damage literature disagrees: the Internet Center for Wildlife Damage Management reports that owl models, rubber snakes and similar devices have little or no effect on pigeons, and FWP says decoy owls work only for a short time. We would not rely on one. See do bird scare devices work.

Why should you call the installer before anything is attached?

Because the array is under warranty and someone else's name is on it. The Department of Energy guidance notes that complete systems are often warranted by the installer for the first year, after which the manufacturer warranties on the modules and the inverter pass to the owner to enforce. It lists enforcement of warranties as an ongoing maintenance task. Anything clipped, screwed or bonded to a panel frame or a mounting rail is a modification, and you want to know in writing how the installer and the manufacturer view it before it goes on.

Ask the installer three things: whether they supply or approve a specific guard for your racking, whether fitting one affects any warranty, and whether they want to inspect the wiring once the nests are out. HJ Property Care does not do solar installation or electrical work, and we do not remove or lift panels. Our part is the bird side: identifying the species, clearing nests where that is lawful, cleaning the roof and gutters, and fitting exclusion mesh in whatever manner the installer accepts.

When should the work be done?

The Department of Energy guidance says to schedule rooftop activities and the removal of nests according to nesting season timing. For pigeons, which the Montana Field Guide says form pairs from February through September with overlapping broods, there is no clean off-season, and since they are unprotected the work does not have to wait for one. The practical rule is to clear and close in one visit, so birds are not left an open cavity to rebuild in.

Weather sets the calendar more than birds do. Roof work on a pitched, panel-covered roof needs dry footing, and in western Montana that means planning around snow and ice. If a native species turns out to be nesting under the array, the work waits until that nest is empty.

How should the panels and the roof be cleaned?

Gently, on the glass. The Department of Energy guidance says to clean modules with plain water or mild dishwashing detergent and not to use brushes, solvents, abrasives or harsh detergents. It notes that most owners rely on rain alone, with cleaning added where local soiling justifies it. Check the module manufacturer's instructions first, since they govern the warranty.

The roof and gutter cleanup under and below the array is a droppings job and should be done wet, with protective equipment and contained disposal. Dry scraping or blowing it off the roof spreads dust over the yard and into open windows. Our bird dropping cleanup page describes the method, and bird dropping health risks explains the reasoning.

Who does which part?

The solar installer or electrician owns the panels, racking, wiring and warranty questions. A roofer owns damaged shingles or flashing. We handle the birds, the mess and the mesh under our bird mitigation and bird netting and exclusion services, coordinated with whoever holds the warranty. If you are planning a new array, ask the installer to price a perimeter guard at installation, when access is easiest.

More on pigeons and other birds on buildings is in the Montana Bird Control Guide.

Call HJ Property Care & Tree Service at (406) 215-7319 or request a bird assessment and we will identify the species, the access points, and what will actually stop them.

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