Reminds me of something I once heard, but never checked up on. People's habit of feeding song birds has lead to bird populations higher than what the natural bioscape can support.
makes sense i suppose. but really, what is natural? some think that man and his actions are not for some reason.
Feeders@21 I think this is a topic that if, treated with appropriate detail, would cause readers here to fly away Species making winter migrations to the tropics have been generally in decline for decades. Apparently linked to habitat losses down there. Many song bird species never set claw in cites, so don't know that feeders even exist. The ones that do, certainly recruit to the resource. I think feeders could only boost their populations if they were year-round residents. And if the hotspot did not draw in predatory birds and cute (fanged) kitties. One thing that does pop up, is that bird feeders (solid or liquid) ought to be kept sorta clean. Weekly bleaching would be good. It is 'novel' for birds to spend so much time together at permanent structures. One sick bird can be very effective at disease transmission to other birds. It is just a thing about ecosystems. it is very difficult to alter one part of them, without having effects (often unanticipated) on other parts. +++ Feeder story: I sent a student out on his own for a week of data collection in the Great Smoky Mountains. We were actually concerned about bears. But no, he had a grand time and even put out a hummingbird feeder. Part way through he ran out of real sugar and started to use some non-caloric sweetener. He was actually proud of that, when describing it. I did not kill him, but our later discussion on the topic was very serious.
bps did a great show on hummingbird migration. they were tagging them down in the carolina's i think. that would interest me.
A 2001 Prius got its nickname (borrowed by me here) with the absurdity of hummingbird energetics in mind. Heart rate 1000 bpm 'at work' drops to 50 during nightly torpor. They even shut down their friggin' kidneys! One gram of fuel translates into a lot of 'range', but in migration (at least) they face death by starvation every day. A lot of tropical plants have brief (and overlapping) flowering seasons. Works for them (manipulate pollinators) but puts hummingbirds in a bind. So they ship out, poleward, for nectar somewhere else. When there is an intervening desert, things can get dicey. But assuming that the (absurdly cute little) eggs hatch, parents quit the flowers (and sugar feeders) and switch to insects for baby food. Nitrogen. Then, they do it all again. ++ By the way, those big windmills, don't paint 'em red, OK?
i'm amazed at how friendly they are. and entertaining. we have a feeder about 6 feet from our patio chairs. they come and sit and drink, look around, play with each other, hover over us (are they studying us?) and head back out for more food.
Play - hummingbirds are quite aggressive when food sources are at 'normal' density. Some feeder setups are very large, basically too much for everybody, and then the birds are playful. Good example at Monte Verde in Costa Rica. If the bird on bird action happens after feeding, it sounds like play to me Studying you - I do not know, maybe they hover over other objects that you don't see. Also known as the 'why do street lights go out when I pass under them?' effect. General impression is that your feeder supply is large compared to your local bird population. Curious what is the largest number you have seen on site at one time? ++ Anyone who has seen the display of hummingbird nests at Phantom Ranch (bottom of Grand Canyon) gets an automatic like. Tell us what the nests were made from? ++ Strong urge to talk about bird lungs plus air sacs that enable the one-way flow system. Some dinosaur (ancestors) had the same, but no one has the slightest idea why dinos would do that Best website discussion I saw on the subject spent half its time whining about creationists' view of the matter, so I don't link. Focus, me hearties.
