October 9, 2012
A version of this article appeared in Volume 8 of Winter Bird Highlights.
Some FeederWatchers are content to count any species that visit their feeders. Others, however, are continually plagued by so-called “pest” species, be it grackles, starlings, pigeons, or the ubiquitous House Sparrow. Although these birds can be interesting and attractive in their own way, and FeederWatch welcomes counts of this species so that we can monitor their populations, House Sparrows are an invasive species, and they can act aggressively toward smaller and more timid feeder birds.
House Sparrows are native to Europe and Asia but were introduced to Brooklyn, New York, in 1851. By 1900, the species had already spread to the Rocky Mountains. With several more western introductions in the 1800s, House Sparrows easily spread across almost all of North America—only absent from Alaska and Northern Canada. House Sparrows spread so quickly and so successfully across the continent because of their preference for human-created habitat. House Sparrows actually prefer to nest in man-made structures such as eaves and street lights, and they will feed both at bird feeders and from scraps and trash on the ground. In fact House Sparrows are only found within the immediate vicinity of humans—they are absent from heavily wooded areas, grasslands, and deserts.
House Sparrows can sometimes discourage native birds from visiting feeders, and during the breeding season they will sometimes oust native species from nest boxes. For these reasons, FeederWatchers who have been plagued by House Sparrows sometimes become frustrated by the little black-bibbed birds. One solution is to shy away from millet and to sweep away any seed that accumulates below feeders. However, there may be another solution to the House Sparrow conundrum—feeder halos.
The idea for feeder halos stems from techniques used to keep gulls away from landfills and reservoirs where wires are hung in the air to deter the unwanted birds. University of Nebraska, Lincoln, researchers applied this same technique to bird feeders in the hopes that House Sparrows would react similarly to the gulls. The researchers found a significant reduction in House Sparrow visits to the feeders in their study. The hypothesis behind the halo is that House Sparrows perceive the wires as a possible hindrance to rapid escape from the treated feeder. Interestingly, the effect seems to be relatively species-specific, as other species such as finches, cardinals, and native sparrows are unperturbed by the wires. The effect may also have something to do with the angle at which different species approach feeders.
Some FeederWatchers have reported success with sparrow halos. Brian Winters, a naturalist at River Trail Nature Center in Northbrook, Illinois, reported on the feeders at the nature center. In the first few weeks of using the halo, the nature center saw some results. “At first, the House Sparrows seemed to completely avoid the halos. Now they are visiting… but at a reduced rate.” The reduction of House Sparrows means other birds may have a better chance at the feeders. “We have seen other species able to find an opening whereas before they could not,” Brian reports. Linda C. Brennan of Coventry, Rhode Island, notes, “It seems to be working. I haven’t seen any House Sparrows at the feeder with the halo. We are even getting fewer House Sparrows at our other feeders.” Linda has also noticed a greater number and variety of native birds at her feeders.
If you would like to discourage House Sparrows from your yard, try using a halo baffle. You might be able to buy one at a specialty bird-feeding store, or you can make one. Start with a sturdy object—a baffle or a clothes hanger bent into a circle—and hang the ring above your feeder. Attach wires to dangle from the ring. Don’t use fishing line as birds can easily become entangled; instead use something like hobby wire, which can be purchased at craft stores. Shinier wire may also be more effective, as visibility of the wire may play a role in keeping the sparrows away—the glittering of shiny wire could make it harder for the sparrows to determine where the wire is, which might make the sparrows more wary. Be sure to weight the wires with something like fishing weights or washers, or fix the wires to the ground, in order to prevent entanglement. Space lines 30–60 cm apart (1–2 ft) for optimal results, based on the body size and wingspan of the House Sparrows.
Be aware, however, that halo deterrents may become less effective over time. As with any obstacle, it’s possible that the birds may learn to become more comfortable with the wires as time goes on. The University of Nebraska researchers found that the wires were not effective in deterring juvenile House Sparrows or breeding females, perhaps because juvenile birds are less wary of dangers and adult birds become more likely to take risks during breeding season in order to care for young.
Have you used a halo to attempt to deter House Sparrows? Let us know about its success or failure in the comments below.