It seems that the previous property manager here had a couple of feeders hung outside the bedroom window and, after having several "inquiries" I gave in and put up a feeder in early spring. Evidently I make a mean nectar because it looks like happy hour every hour from dawn to dusk out there. What was originally a clean and refill every three days (I use a 500ml bottle feeder with perches) has gone crazy over the last few days. Two days ago the little guys and gals finished off an entire bottle (a bit over 16 oz.)! So I put a second feeder up yesterday and today they went through all of one and 60% of the new one - sheesh!
I get four types here: Anna's (a year-round inhabitant), Rufous, Calliope and Black-Chinned. A little bit of geek math based on average weight and the fact that the little hummers can eat between 1/2 and eight times their own body weight, means that I have between 26 and 419(!) of the little guys and gals. One estimation method is to assume 1,000 birds per gallon of nectar consumed in a day, another takes the maximum number seen on the feeders at one time and multiples that by six. These methods would mean I still have between 42 and 200 little hummers around here!
Any way you cut it, I've got quite a circus going on outside my windows right now. I refilled during the day last week and had five hovering 1-2 feet away from my head while I was putting the feeder back up (that's a weird feeling!). Yesterday and today it looked like a swarm of (very large) bees out there - unbelievable.
I feel sorry for those of you in the UK since hummingbirds only exist in North and South America. These little ones are fun to watch!