As we have discussed in the past, the little adult psyllids that emerge from the nipplegalls on hackberry leaves overwinter in the bark of hackberry and nearby trees (especially spruce). In spring they come out of their bark hiding places, mate, and the female adults lay eggs on swelling hackberry buds. The resultant nymphs tunnel into the needle and cause the formation of the next crop of leaf galls.
On February 19 (last Friday) in Fort Collins' Grandview Cemetery (Larimer) a couple visiting birders and I noticed some bird species known to be psyllid gleaners (Brown Creepers, Mountain Chickadee, Golden-crowned Kinglets, and Ruby-crowned Kinglets) acting a little differently than they have been all winter. During cold days over the last 3 months or so, psyllid-seeking birds they usually confine their hunting to the interior of tree crowns, especially up high. The other day they were at the base of the trunk of a chronically-infested hackberry and on the ground under that same tree. The tree where we saw this is the one that had the Cape May Warbler in late fall 2014, for those of you who saw that special psyllid-eating bird. I checked a few polished stone grave markers nearby (where adult psyllids are easier to see than on bark) and, sure enough, saw a few adult psyllids out and about. This seems very early, but given the warm temperatures we've been having, maybe not all that surprising. These insects are laden with anti-freeze chemicals and will probably survive the next cold snap by simply going back into their bark niches.
At any rate, the lower trunks of hackberries might be worth checking for gleaners, at least until the weather gets cold again.
Dave Leatherman
Fort Collins
On February 19 (last Friday) in Fort Collins' Grandview Cemetery (Larimer) a couple visiting birders and I noticed some bird species known to be psyllid gleaners (Brown Creepers, Mountain Chickadee, Golden-crowned Kinglets, and Ruby-crowned Kinglets) acting a little differently than they have been all winter. During cold days over the last 3 months or so, psyllid-seeking birds they usually confine their hunting to the interior of tree crowns, especially up high. The other day they were at the base of the trunk of a chronically-infested hackberry and on the ground under that same tree. The tree where we saw this is the one that had the Cape May Warbler in late fall 2014, for those of you who saw that special psyllid-eating bird. I checked a few polished stone grave markers nearby (where adult psyllids are easier to see than on bark) and, sure enough, saw a few adult psyllids out and about. This seems very early, but given the warm temperatures we've been having, maybe not all that surprising. These insects are laden with anti-freeze chemicals and will probably survive the next cold snap by simply going back into their bark niches.
At any rate, the lower trunks of hackberries might be worth checking for gleaners, at least until the weather gets cold again.
Dave Leatherman
Fort Collins
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