The summer blooms are at peak color in the garden, and there is a bouquet of red, pink, purple, yellow, orange, and white right now. They are a month late, but finally we are seeing quite a few bees of all sorts and a few butterflies in the garden. For the past week, another tiny visitor has been making the rounds of the red and orange flowers.
After all that feeding, it’s time for a rest, to process some of that liquid so she doesn’t have to carry it around.
Ruby-throated Hummingbirds weigh less than 4 grams, but can store up to 1 ml of nectar in their digestive tract while they process the nutrients in the nectar. If we assume that 1 ml weighs about 1 gram (as plain water would), then the bird has just gained 25% of its body mass during its feeding bout, and it doesn’t make sense energetically to try to fly with all that extra weight. The Hummingbird gut is specially adapted to absorb sugar and other nutrients in nectar across the lining very quickly and efficiently, removing more than 90% of the calories in the nectar on its first pass through. Then the excess liquid in their diet can simply be excreted in just a few minutes.
Doesn’t that give them a sugar-high? I suppose it does, but hummingbirds can also quickly metabolize that sugar and turn it into body fat, which they will use to keep them warm overnight. Altogether an amazing metabolic marvel, the mighty mite.