What Makes a Habitat Successful?

A successful habitat allows the wildlife living within it to forage, reproduce, and raise their young to adulthood. In order to do so a habitat has to provide four things: 1. food, 2. water, 3. cover, and 4. space. A habitat that is deficient in any one of these categories will see less biodiversity and fewer organisms using that space. In our cities and suburbs it can be hard to see where wild animals might find the resources we need to thrive, but if we look closely around our human spaces, we can see where wildlife can find room to thrive.

Many birds are cavity nesters, meaning they build their nests in holes (usually in trees). Some birds, such as woodpeckers, can make their own holes, but many species rely on pre-existing holes made by fallen limbs or other birds. Human-made nest boxes are readily accepted as alternatives to tree cavities, especially along trails where trees with fallen limbs and rotten cores that would normally provide good nesting opportunities have been cut down due to safety concerns. Some of the most common inhabitants of ready-made cavities are Chestnut-backed Chickadees and Western Bluebirds.

While bird baths are good, flowing water is even better when it comes to providing resources for local and migratory birds. Moving water attracts more visitors than stagnant water, and migratory birds often rely on streams and rivers as stopover sites where they can rest and refuel. The increased biomass surrounding bodies of water provides better food and shelter than areas lacking in water. Flowing water helps bird with their preening activities, flushing out parasites from their feathers, as well as attracting water-loving insects like damselflies and water boatmen who are an important food source. Swallows and Black Phoebes are two of our local birds who are particularly attracted to flowing water. 

With many of our neighborhoods built around our creeks and rivers, these spaces offer a great opportunity to see some of our larger avian neighbors too, with egrets and herons hunting along the shores of our waterways.

Some plants have close relationships with wild animals. This can involve a preferred source of food, a favorite source of nesting material, or even a preference for a single type of tree to nest in. Plants that require pollination have evolved to rely on certain bird species to perform this vital task. These plants evolved specific ways to attract their avian pollinators. Sticky monkey-flower, for example, has tubular flowers that hold nectar to attract Anna’s Hummingbirds. In the Spring, this nectar is an important food source for the hummingbirds. When these plants are absent, hummingbirds may struggle to find enough food to fuel their high-energy flight.

Some birds even have dependencies on certain kinds of plants. The Hooded Oriole only nests in palm trees, weaving their nests to the underside of palm fronds where they will be hidden from view and safe from the elements. Historically this bird lived in Mexico, but the popularity of palm trees in landscaping has brought these brightly colored birds up north to us! Take a walk around your local palm trees and listen for their chattering calls, or try to attract them to your yard using orange slices or jelly.

Trees and bushes provide excellent nesting sites for many birds, but some species prefer geologic features like rock faces. White-throated Swifts, for example, use their saliva to glue their small cup nests of twigs and moss to vertical surfaces. In urban settings, they happily nest on artificial cliffs such as the underside of overpasses or beneath buildings’ eaves. Without suitable nesting sites, these birds can be forced out of an area. Bird spikes and other deterrents can flush all but the most tenacious species out of urban settings, reducing biodiversity. 

Peregrine Falcons are another species that utilizes our buildings for nesting space. The fastest birds in the world typically use steep cliffs to protect their nests, and will also use the height afforded by these features to dive down on their prey (at speeds over 200 mph!). While we don’t have many cliffs in our cities, we do have plenty of tall buildings with window ledges that make for nice spaces for these once-endangered birds to nest on.