Feathers were strewn everywhere. Body and head asunder. Something had been eating the skull custard. A murder in my backyard.

I’d been walking my bike to the back patio of my urban home in Seattle when I’d been stopped in my tracks. A bird lay there, dead, left in the middle of the cement. Immediately my mind tore into superstitious, paranoid thoughts. Was this an ill omen? Who was the culprit? The neighbor’s cat, who roams freely, accompanying me while I tend my vegetable garden? Was I responsible because I’d not chased him away? Or was this something entirely more natural, a Cooper’s, a Sharp-shinned Hawk?

This mess was a female American Robin (Turdus migratorius). Most likely the one I’d been watching collect heaping billfulls of earthworms for nestlings nearby. I had a selfish moment of annoyance. I’d just swept the patio, now it was littered with feathers and a half eaten corpse. What a strange reaction to a gruesome death. Annoyance at the inconvenience?

Walking inside, I pondered how I should be reacting. A couple attitudes, moral directions presented themselves.

On one hand, this is just a part of life. Mortality, particularly in short-lived species like American Robins, is commonplace. Death is often apparent during the breeding season. Failed nests, naïve fledglings, there’s a reason many species have large clutches. The American Robin population is generally increasing, so certainly there was nothing to worry about. While I know these things are true, I’ve never been able to fully submit to this scientifically objective tone. I’d argue that most good biologists have emotional attachment to whatever they study and generally care more than their publications admit.

(And, I do enjoy seeing a natural predator catch prey, but that doesn’t mean I relish death.)

On the flip side is my desire to honor or rather cherish all life. Assigning values to different species seems absurd, horrible in fact. Yet we do it all the time, from valuing vegetables over weeds or killing mosquitoes while encouraging lady beetles. Life isn’t so simplistic to totally adhere to one train of thought. I’d be lying if I said that I wouldn’t be more upset if I’d found say a Cooper’s Hawk or even an American Crow dead in my yard.

However, what if I was indirectly responsible for the death of this bird? I connected the dots: petting the neighbor’s cat, encouraging it to come back, giving it an opportunity to catch this mother robin. There’s an entirely different issue here:  this cat was outdoors in the first place. Outdoor pet cats probably kill hundreds of millions of songbirds every year. This is an inflammatory issue, but you can’t ignore that fact that house cats are not natural and can have a serious impact. With an estimated 60 million pet cats in the United States alone (many of course are kept indoors), if even half are outside and kill a bird every year, that’s around 30 million birds dead of just one of many human causes*. I myself have had pet cats that went outside too.

So basically, should I be moved to tears or stoically look on as a trained scientist? As usual, I landed somewhere in the middle. There’s a good chance that if this female had a nest, it would now fail and that was a sad image; baby birds wasting away in the nest. Males do help with rearing young but it’s not typically a one bird job. Yet, as I said, American Robins are extremely common and that this was not a disaster for the species.  However, whether or not we choose to acknowledge it, humans have impacts on other species, even the common ones.

Mulling it all over I’d concluded that another bird had likely killed the robin based on the state of the corpse. The scientist in me decided that I might as well use this as learning experience, I started to do a little research on American Robins.  Maybe I could also figure out the age of the bird or something else. Time for some forensics.

Just as I had that thought, I heard the ominous rush of scavenger wings outside. Crow wings. It doesn’t take long for a mess to be cleaned up. More wingbeats and knocking on the gutters. I crept outside to watch the crow and its prize.  I wasn’t quiet enough. Flushing, it left a robin corpse in the gutter. Maybe that full crop was going to some babies. From death comes life? I continued thinking about how to approach life and death in my backyard and I heard the crow return two more times.

Inspecting my patio a half an hour later, I found no head and no body.  Somehow this resolved the issue for me.

As I stood there with feathers strewn about my feet, Bewick’s Wrens were noisily herding their shakily flighted fledglings about the yard. Death and life were spinning about, even in my urban yard.

* a few sources and extra info for those who get up in arms about cats: http://library.fws.gov/bird_publications/songbrd.html ; http://www.fws.gov/birds/mortality-fact-sheet.pdf ; http://www.motherjones.com/environment/2011/06/cats-tnr-birds-feral