The Ruby-throated Hummingbird numbers are increasing here at my feeders. I made a couple of post a few weeks ago saying that I wasn’t seeing as many Hummingbirds as I usually do. (2016 Ruby-throated Hummingbird and Male Ruby-throated Hummingbird (2016))
Several of you told me that my numbers may increase as these birds start migrating south. It is a little early for migration here in my area, so I’m not sure why I have a few more now. I only had 3 or 4 during the early summer and now I am seeing 6 or 7.
I read that there are differing views in the birding community as to what triggers the start of migration, it is generally thought that hummingbirds sense changes in daylight duration, and changes in the abundance of flowers, nectar and insects. Instinct also plays a role in making the decision to migrate.
I am glad to see more than the 3 that I was seeing the past few months. Maybe I will even see more this next month. I know I live in the National Forest and may not see the numbers that I have seen in other parts of the state.
Ruby-throated Hummingbird Facts
A hummingbird’s ability to hover is due to its small mass, high wingbeat frequency and relatively large margin of mass-specific power available for flight. Several anatomical features contribute further, including proportionally massive major flight muscles (pectoralis major and supracoracoideus) and wing anatomy that enables the bird to leave its wings extended yet turned over (supine) during the upstroke. This generates lift that supports body weight and maneuvering.
Hummingbirds achieve ability to support their weight and hover from wing beats creating lift on the downstroke of a wing flap and also on the upstroke in a ratio of 75%:25%, respectively, similarly to an insect. Hummingbirds and insects gain lift during hovering partially through inversion of their cambered wings during an upstroke. During hovering, hummingbird wings beat up to 80 times per second. (Wikipedia)