Monday, April 12, 2021

Are neighbors to blame for drop in Halo efficacy?

The view over the fence into our neighbor's yard
As always, and in spite of good survey results, we at magichalo.org are striving to learn why there can be a significant difference in House Sparrow (HOSP) behavior from year to year, and from one Magic Halo user to the next.

Starting in 2015, we were 100% HOSP-free at our feeders with halos. Given the success, we designed and produced our own Magic Halos for on-line sale. Then last year, for the first time, our halo efficacy dropped by ~20%. HOSP were now part of the feeder mix, albeit brief visits -- not full time or to the exclusion of native birds. Now in Spring 2021, HOSP are a regular presence, with young adult pairs going around menacing our nest boxes and platforms that are designed for native birds that include Chickadees, Wrens Mourning Doves, Robins, etc. The Halo continues its job in deflecting most HOSP from the feeders, at about 80%.

What changed from 2015-2019 to 2020? We fed through the entire year in 2020, including Summer, which may have contributed to the issue of HOSP juvenile Halo adaption/immunity. But a recent look over our fence may provide an even better explanation. Our western neighbor installed multiple nest boxes, well designed and situated for HOSP. We think this may have begun in 2019, but cannot be certain since we rarely looked over the fence.

Purple Martin house overtaken by House Sparrows
A weakness of the Magic Halo is HOSP juvenile immunity and adaptation into adulthood. If your neighbors are providing cavity nesting sites, they can rapidly multiply, with your yard and gardens as their home territory. If the young birds are using your feeders as juveniles, then it is possible that no counter-measures will deter them, because they will have grown into its presence. This is a theory, that just happens to match the evidence. But it makes a lot of sense.

It is much better not to install a nest box than to allow HOSP to reproduce in one. Unfortunately, many boxes are sold on the cheap, in stores like Home Depot or Lowes. These often have 1.25"+ entrance holes -- the minimum diameter that HOSP can fit through. These (and sadly, many Purple Martin communal houses) end up as breeding meccas for HOSP. Without active education at the point of sale, most buyers believe that they are "helping wildlife" regardless of species occupant. Even some specialty stores avoid the topic, and and even encourage their customers with HOSP feeding and nesting. They may be afraid of the perceived monetary loss (selling less seed). On the other hand, they should know and understand the non-native, invasive and damaging nature of HOSP (and Starlings) on the north American continent. Any gains made by Bluebirds, for example, are largely owed to conservationists who are up to the task of monitoring and evicting HOSP from nest boxes. For those of us living in urban or suburban areas, simply dropping the hole diameter to 1.12" (1 1/8") will safely accommodate native species such as Chickadees and Wrens while excluding HOSP from entry.

As part of our ongoing Halo experiments and efforts at continuous improvement, we began trapping and clearing HOSP from the property in the 2nd week of April. Halo efficacy has returned to almost 100%, given that it disrupted this newly created colony as described above. In a return to years past, we are taking down our feeders for the June-Aug time period. We also wrote a friendly letter to our neighbor, explaining the HOSP problem in the hopes that they will adapt their boxes with hole size reducers and distribute them properly. Stay tuned on these efforts.

Humans created this problem 150 years ago by deliberately releasing HOSP mated pairs in urban centers across the U.S. Now we must try and reduce them, using all the tools in the toolbox. This includes halo/hoop devices, spookers, traps, or whatever means are necessary. Below are several valuable links you can use in your own efforts to control the scourge of HOSP, and maximize your Halo's efficacy and thus help native birds:

Managing House Sparrows (the most comprehensive guide, includes site map and history)
Magic Halo User Guide (measures to improve your Magic Halo's efficacy)
Backyard Birds (YouTube videos that include trapping and eradicating)
House Sparrow Control (Facebook)
Birdhouses, Bird Feeders & Garden Designs for Native Species (Facebook)

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