Black-billed Magpie Behavior & Misc Observations - Arapahoe

[Jared Del Rosso]

In Centennial (Arapahoe County), families of Black-billed Magpies have begun flocking together at dusk. Though I haven't been closely attending to magpies over the five or six years I've lived here, this does seem like an annual ritual. Looking back at eBird, I've seen flocks of 20-100 magpies in July. Tonight, 20-30 were hanging around the power lines running across University, just north of Arapahoe.

But more notable (to me, at least) was a visit from an apparent magpie family a few mornings ago. The family sought food in my yard. Who knows what. I saw one with an earthworm. Others were in the chokecherry shrubs. But the young did the young corvid thing, exploring anything that might be food. Two tugged at a bright orange tag, still affixed by a plastic ring to a solar light. (They failed to break the plastic ring and win the cardboard tag.) Then, one found a scrap of paper and worked at it for a time, before another stole it, surveyed it, then let it be.

My favorite moment, though, came when four of the magpies lined up outside the fence keeping my chickens penned in. My four chickens lined up inside the fence, staring back at the magpies. The stare down lasted a hilariously long time. I wish I knew what messages passed between the two species.

Around town, otherwise...

• For the past month or more, most evenings, deep into dusk,  a male Broad-tailed Hummingbird has passed over my yard. I just hear it go, trilling. I'm not sure what the daily passage means.
• An unidentified hummingbird has been visiting my wildflower garden daily. It doesn't look like a Broad-tailed, but I've only observed it without binoculars or camera, so I don't have an ID on it. It visits Scarlet Bugler (Penstemon barbatus), California fuschia (Epilobium canum), and Rocket Larkspur (Consolida ajaci). A few days ago, I had the good fortune of watching it feed on the penstemon from 4-5 feet away. Today, it kept its distance. It also chased around a House Wren, for whatever reason.
  
• That House Wren was mimicking a Rock Wren this morning. Having caught something (I was too far and without optics to see what), it perched on a landscaping brick and kind of, sort of bobbed, as Rock Wrens do. It wasn't as relaxed a bob as a Rock Wren does, and I wondered if it was trying to draw the attention of a young or a mate, to whom it might be bringing the food?
• Two nights ago, a Common Nighthawk flew northwest over my home. I expected to find it somewhere over Orchard Rd and University, as I frequently saw flocks of the bird there last year. So I headed out and indeed found four nighthawks feeding low over a cul-de-sac off Orchard Rd. I hope to survey this area over the next week or so and see if nighthawks regularly visit this area.
• Today, a Chipping Sparrow was singing at Willow Spring Open Space in Arapahoe.  I also hope to visit the dam there to survey for nighthawks, as it tends to be incredibly buggy. Last October, I saw my last nighthawk of 2020 feeding over it. This is a neat spot -- it's a human-made dam, with a drainage, with a beaver dam built nearby. So there's often a pool of water there. I've seen Great-horned Owls and accipiters perched over it, raccoons amid it, coyote paths, Wilson's Snipe feeding in the water, families of relatively tame Song Sparrows feeding in the weeds, and, in the winter, Northern Shrikes. 

- Jared Del Rosso

Centennial, CO