Okay, let's get a couple of things out of the way first:
- I am not in this to torture birds. I have a deep love for all animals, especially birds. I'll explain myself further in the body text below.
- I have not done anything yet, nor will I until I carefully consider all facets of this question - including the ethics. Heck, I don't even know how I would do this.
Now, some explanation. House sparrows (HOSP) are a notorious invasive pest in North America. They compete with local cavity nesting songbirds such as bluebirds and chickadees for available nest space. Sometimes, this competition becomes lethal - HOSP are highly aggressive and there are many documented cases of them trapping native songbirds in their nests and murdering both adults and chicks as well as destroying eggs. They also crowd out native birds at feeders, though this anthropocentric concern is not a crime that warrants the death penalty. Trapping and euthanizing of HOSP is entirely legal and often recommended as the most effective strategy for protecting local native songbird populations - at least, for bird-lovers who have the stomach for it.
Problem is, I don't know if I do have the stomach for it. As mentioned, I love animals - maybe a little too much, because despite knowing how detrimental they are to my beloved local songbirds I'm not sure I can bring myself to kill a captured sparrow. I do, however, know two fluffy little killing machines who stare with palpable longing at every sparrow that lands outside my windows.
Now, cats are their own problem for bird lovers - they can decimate a local bird population and their murder spree doesn't discriminate between invasive and native/threatened birds either. So mine are kept indoors. But I do feel bad keeping them cooped up; despite my best efforts to play with them and provide them stimulation, they're definitely not leading as interesting a life as if they were allowed to roam free, and studies on free-roaming cat ranges shows that an apartment is definitely smaller than the roaming space they'd like to have.
Before I draft up a plan to capture local sparrows and execute them by throwing them into gladiatorial combat with my cats, though, I've got a number of questions. The obvious one is the ethical dilemma. Feeding HOSP to a predator is at least natural, and it kills two birds with one stone: gets rid of sparrows without forcing me to kill them myself, and provides my cats with some welcome stimulation. But there's no denying that it's not a very merciful death, especially given how cats like to play with their food. I'm not sure Pets.SE is the place for complex ethical dilemmas, though - maybe I'll post a corollary to this question on Philosophy.SE. There are a number of other more mundane aspects to this, though:
- Is this dangerous for the cats? They're entirely indoor cats fed on mostly wet food, so they aren't used to meat with bones or feathers.
- Do I run the risk of exposing my cats (and myself) to disease? For example, I know outdoor cats typically pick up Toxoplasma gondii from their food (which picks it up from soil, I think).
- Is this potentially dangerous for the cats, given that HOSP are highly aggressive and my cats are not the brightest, despite what they think?
- Will this spoil the cats for live prey? I want them to get more out of their lives, but if I start this and then later stop, are they going to feel all the more captive because they know what they're missing?
- Are there other factors that I'm not considering, but should be?
Rest assured that the ethical aspects of this are heavy on my mind, and I'm not going to go ahead with something like this lightly. I still haven't decided whether this is something I'm comfortable doing at all. But I figured that there's no sense grappling with the complex moral dilemmas until I know whether this is even a reasonable thing to consider at all, ethics aside.