A significant danger to wildlife is poised by open 4” vertical PVC or Big-O pipes, and open valve boxes. Snakes, amphibians, bats, birds and many sorts of invertebrates in valve boxes have been found.
Plastic PVC pipes have been used as valve boxes, piezometers, and mining claim markers for some time. Onsite installers and mining claim-holders use 4-inch diameter PVC plastic pipes because they are light, inexpensive, and easy to see. If uncapped, they are also bird and wildlife-killers.
Small birds, mostly cavity-nesters, frequently investigate these pipe-openings, often after first perching on top. Once they enter a pipe, the birds become trapped; the width doesn’t allow for wing-opening, and the sides are far too smooth to allow climbing out. The pipe becomes a deadly trap.
For example, two inspections in Nevada of 1,177 pipes in 2008 and 2009 revealed 957 dead birds. And again last month, 854 pipes inspected revealed 879 dead birds. Ash-throated Flycatchers and Mountain Bluebirds dominated the mortalities, but other victims included woodpeckers, shrikes, wrens, sparrows, Green-tailed Towhees, and even Western Screech-Owls.
According to a 2006 Statistics Canada survey, approximately 20% of the 12.4 million households in Canada (or about 2.5 million) use onsite systems.
There are about 115 million households the US of which about 25% use onsite.
Make sure all vertical pipes and valve boxes are covered!