Re: Eastward Range extension.....

[Robert Righter]

Hi:

David Leatherman in his recent post pointed out detecting movement of traditional mountain and foothill species downslope to the plains. This phenomena has previously been posted on Cobirds this summer with observers commenting on how the mountain species are just not present in the numbers they use to be. Recently I was birding in Grand Co. and the sparsity of mountain species was impressive, the forests were very quiet.

One possibly explanation could be since the West has been so dry for quite awhile and the abnormally high heat has just sucked the moisture right out of the ground dramatically affecting the soil composition and thus effecting the health of the forest and consequently it’s bird life?  Any other thoughts? 

Bob Righter

Denver CO

[Diana Beatty]

If it is a long term phenomenon reaching a peak vs. short term, it may be worthwhile to look at what has been happening with precipitation in the longer term as well.  In general, the southern parts of the state are getting drier.  Only the northern front range seems to be holding own or even gaining slightly at this scale, perhaps - but this often includes the northern mountain counties as well - an absence there may suggest net precipitation is not the whole story but perhaps increases of extremes in the fluctuations of it and sensitivity of certain habitats to those extremes absent manipulations by man in urban areas where we artificially add water to the system (although we may not be able to continue to do so much longer) which can lead to extreme events like beetle kill, forest fires, mismatch of food supply with timing, etc.:

https://www.weather5280.com/2021/07/21/analyzing-colorados-precipitation-trends-over-the-last-125-years

Diana Beatty

El Paso County

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All that is gold does not glitter, not all those who wander are lost; the old that is strong does not wither, deep roots are not reached by the frost.