bird mortality s

Habitat loss ranks number one among the human-associated threats to wild birds. In Ventura County alone we have lost 85% of our grasslands, 90% of wetlands, and 95% of riparian habitat.  Habitat loss is attributed to urbanization and other development, intensive agriculture, and roads.  Habitats are also degraded by the introduction of invasive plant and animal species that can impact nesting, foraging, and roosting habitats for birds.


cat killing bird

According to a study published recently in Nature, cats kill between 1.3–4.0 billion birds annually in the United States. This magnitude places cats among the top sources of anthropogenic bird mortality; with window and building collisions. Introduced to the United States with European colonists, domestic cat numbers have tripled in the past 40 years. Today, more than 100 million feral and outdoor cats function as an invasive species with enormous impacts.  A technique called Trap, Neuter, Release (TNR) has been incorrectly suggested by some as a solution to the feral cat problem

Volunteers catch feral cats, neuter them, and re-release them. The idea is that the colony will diminish over time, and eventually disappear. Unfortunately, studies have shown that this technique does not work. It is very difficult to trap and neuter all the cats, and the colonies become an attractive dumping ground for people looking to abandon unwanted pets. As a result, the colonies often grow larger. TNR does not address the fundamental problem of cat predation on birds and other wildlife. It is also inhumane. A better solution is to trap and neuter feral cats, then relocate them to enclosed cat sanctuaries or shelters, or to adopt them out to safe and comfortable

Read more: 
Cats Indoor
The Impact of Free-ranging Domestic Cats on Wildlife of the United States


window strikeThere are two main types of window collision mortality. The first happens by day, when birds crash into windows in homes and buildings because they see reflections of the landscape, or see through the glass to potted plants or vegetation on the other side. The second type happens by night, when nocturnal migrant birds (including tanagers and warblers) hit lighted windows that jut into their airspace. Some of these nighttime collisions are due to simple chance, but much more often the nocturnal migrants are lured to their deaths by the lights. For reasons not entirely understood, lights divert nocturnal migrants from their original path, especially in low-ceiling or foggy conditions.

Safeguarding Your Windows for Birds

Window strikes are something you should be aware of and try to prevent. Start by identifying dangerous windows. Large picture windows or a pair of windows at right angles to each other are usually the worst culprits. Go outside near your bird feeders and look at your windows from a bird’s point of view. If you see branches or sky reflected in or through the glass, that’s what the birds will see too. Cover the glass with a one-way transparent film that permits people on the inside to see out, but makes the window appear opaque on the outside. Put decals, stickers, mylar strips, or other objects on the outside surface of the window.

These are only effective when spaced very closely. Some stickers are colored in the ultraviolet spectrum—these appear transparent to our eyes but are visible to birds. Placing just one or two window stickers on a large window is not going to prevent collisions—the stickers must cover most of the glass with the spaces between too narrow for birds to fly through. Avoid visual paths where birds can see sky and greenery. Bright windows on the opposite wall from your picture window may give the illusion of an open path to the other side. Closing a window shade or a door between rooms can sometimes solve the issue.

Find out more about window decals:
Window Decals for Bird Strikes
Stop Bird Collisions
Products to Prevent Birds from Hitting Windows


Wildlife poisonings have been documented in over 25 wildlife species including Golden Eagles, Bald Eagles, bobcats, mountain lions, coyotes, foxes, black bears, Cooper’s Hawks, Red-shouldered Hawks, Red-tailed Hawks, owls, raccoons, skunks, squirrels, opossums, Turkey Vultures, and Crows. If raptors (birds of prey) ingest enough poisoned rodents, the poison accumulates in their system and they will die. If the raptor is taken to a wildlife rehabilitation center there is not much they can do medically to save them; the internal organs fill with blood and the bird will bleed to death.

There is no rodenticide that does not present a risk to wildlife, pets, and humans. At present, the strongest data points to anticoagulant rodent poisons as being the most damaging to wildlife. Second-generation rodenticides are still sold in bulk at agricultural supply stores. First generation rodenticides are still sold at major stores.

Second generation. Common active ingredients are in this category: brodifacoum, bromadiolone, difethialone, and difenacoum.

First generation. Common active ingredients are diphacinone, chlorophacinone, and warfarin, bromethalin. These are less potent but still cause severe damage to all organisms.

rtha mouse  poisoned RTHA 
Red-tailed hawk is one of those affected by rodenticide
because they eat rats and mice. 
This Red-tailed Hawk died of internal bleeding after
eating rodent poisoned by anticoagulant rat poison.
Photo by Alison Hermance 

 all things are connected:

Diagram taken from Urban Carnivores

For more information on rodenticides and safer pest removal visit:
California Fish and Wildlife
Safe Rodent Control
Poison Free Malibu


  • Have a pet cat? Keep your beloved pet inside and this will benefit your pet, birds, and other wildlife
  • Help spread the word about the importance of keeping pet cats indoors.
  • Learn and share information about “Trap, Neuter, Release”, a cat management program that has been proven ineffective, yet continues to be promoted by cat activists.
  • Remove bird baths, bird feeder, and bird houses if you decide to let your cat roam.
  • Stop using poisons to kill rodents.
  • Become educated on this topic and share your knowledge with others.
  • Become involved in groups that strive to eliminate commercial poisons.
  • Do not overfill dumpsters, which can attract rodent pests.