I think these birds may include Rufous and Broad-Tailed Hummingbirds of both sexes but that's by no means an authoritative identification.
I'm "way out on a limb" with the following analysis but my identification points are:
Rufous identification points:
1. Our host, Tom, called it a Rufous.
2. Bright orange-red gorget.
3. Range match much better than Allen's.
4. Broad abruptly-tapering tail feathers (seen in one of the photos).
5. Consistent behavior of dominating the feeder. The behavior was so striking that guests variously described him as a "jerk", etc.
Broad-Tailed identification points:
1. Bright red gorget on some birds. Those with only black throats appear otherwise identical to my eye, notably including size. I think some of the photos may even be of the same bird: red in one, black in the other. If true, then lighting may have enabled or supressed the iridescent red flash.
2. Range match better than Ruby-Throated. Despite being a native Westerner, I've spent most of my life in Eastern bird ranges and my first thought on seeing these birds was "Ruby-Throated". Naw, maybe not in Pagosa Springs.
3. Clearly larger size than the Rufous. If these were Rufous and Ruby-Throated side by side, I'd guess the sizes would be much the same. As it was, the little Rufous was clearly smaller than all the other birds.
4. Maybe some flashes of white near the end of tail feathers.
5. Loud high-pitched drumming from the wings in flight. The noise was very striking, enough to make one want to duck the "incoming" object.
Female identification: Way beyond me.
(These web site images are all very, low-res versions. They don't do justice to the Uzi but the resulting bandwidth and disk usage are modest.)
Copyright 2004, 2005 Carl W. Cole
If I keep a green bough in my heart, the singing bird will come. ~ Chinese proverb