[cobirds] Denver area rarities

My friend Boris and I went to Denver on various missions today.  

One, we wanted to visit the site of a true leafy mistletoe infection near the DU campus.  This was brought to my attention by birder Jared Del Rosso, who alerted noted a mistletoe clump growing on a crabapple in the median on Evan Avenue by DU.  Colorado has a handful of native dwarf mistletoe species on pines, Douglas-fir and rarely spruce.  We also have a native "leafless leafy" mistletoe on juniper.  But the mistletoe Jared spotted is the eastern, "Christmas kissing" type with leaves and white berries (Phoradendron flavescens).  In my time since 1974 as a forester concerned with insect and disease issues of trees, this is a first.  I have heard from others that this may have also occurred in CO on a few other rare occasions.  The seeds are sticky and adhere to the feet of birds, with birds, thus, being a means of spread.  It can also be spread by passing thru the gut of birds in their droppings.  Since this mistletoe does not a occur naturally within hundreds of miles of CO (closest place I know is along I-25 s of Albuquerque along the Rio Grande on cottonwood), it is likely the DU infection came in on nursery stock, was missed during inspection and has slowly grown on this planted tree for years.  I would estimate the tree's age to be at least 15, maybe more.

Two, we also chased a couple lifers for my friend who is a beginning birder but knows more about insects than anyone I know.

Pyrrhuloxia was still present at the south end of Newton.  It hung tight in a shrub on the north side of the southernmost house on the east side of the street.  The shrub appears to be a chokecherry or at least something in the genus Prunus.  We probably would not have seen it had the bird not vocalized both song and call.  I saw the bird in Grant, CO many years ago but it was a major thrill to see this one.  Lots of weed seed in the area including wild sunflower, Kochia and pigweed.  However, I have to wonder if it also likes fallen fruit in the leaf litter of the cherry (in addition to store-bought sunflower seed, of course).

We struck out on the Pine Warbler at Fort Logan (the area we searched for about half an hour was near the Oklahoma Street parking circle in the southwest corner of the complex).

We had two Dunlins on the S. Platte River e of Centennial Park.  Also on the river e of the park was a Spotted Sandpiper (couple hundred yards n of bike trail bridge over the river).  The latter may be a known bird but it surprised me.  I had not been to Centennial Park since the famous December 2013 Prothonotary Warbler which ate buckthorn fruits, with legally off-leash dogs zooming around at all times in what was a thoroughly surreal situation.

Dave Leatherman

Fort Collins