NATURE NOTES – Number 50 August 14, 2022
Introduction:
As summer starts to turn into fall, nature gives us new perspectives on a lot of things around us: leaves are changing colors, less daylight each day, falling temperatures, young animals are maturing, and many birds (about half of our North American species) are thinking about booking flights south. Let’s focus on one of those birds and its travel plans:
Our Current Topic: Hummingbirds and Migration
First let’s explore our only hummingbird in the Eastern U.S.: the Ruby-throated Hummingbird. While other parts of the country, especially the Great Southwest, have several species of this tiny creature, we can focus on one species here in Virginia. Note, however, that it is not terribly uncommon to find one of these western species in the east, especially in late summer-early fall. So if you see something that does not match the standard for a Ruby-throated, you may have seen a “rare bird” for our region. These Ruby-throated Hummingbirds are common in the forest as well as around our homes. A simple feeder of sugar water on your deck or patio will usually attract regular visitors that can entertain you for hours as they buzz right up to your face to check you out while maintaining a wing beat of 55 beats a second, then speed off in pursuit of an insect or another hummer that got too close to “their” feeder. They are aggressive as well as curious of new things. Flowers, especially red ones, will attract this less-than-4-gram sized bird. The males and females are both metallic-green, but have difference in throat color and tail features. The ruby throat is not always apparent on the male, and in certain light conditions can appear black or dark purple, but not white. The females and immatures have a white throat. The males also have a tail that appears to be spread out sort of fan-shaped, and marked with white spots on the end. The females have an all-black tail that is not fanned out, but stubbier looking. In our area, these birds usually arrive in the first half of April from their wintering grounds in Mexico or Central America. By late August, early September, they are looking to begin that long journey again where they can spend the winter feeding on the flowers there that are in full bloom. But, and this is an amazing part of nature, you might very well see the very same humming birds next spring when they return to the very same feeder and nesting site they left 7 months earlier. Scientists (ornithologists) have determined that, somehow, these birds frequently find their way back to their exact site year after year. While the average life span is only 3-4 years they might live, if they are lucky, for 5-6 years, making repeated trips each spring and fall over the Gulf of Mexico. This long-distance feat is part of the overall migration that occurs with many bird species each year. The reasons for the migration are rather well known: food and nesting sites. What is more of a mystery, is how they accomplish this long and dangerous trip (predators, foul weather, tall buildings, wind turbines). A number of factors have been studied and it appears that there are a number of ways in which birds navigate these journeys, perhaps different ways in different species, and probably using a combination of the following factors: position of the sun and stars; magnetic fields given off by the earth; visual landmarks; an inherited genetic “compass” of sorts; and perhaps other factors we don’t understand. So if you have a scout that gets interested in nature and wants something to pursue as a career in nature and science, have him or her focus on learning more about how birds migrate. We are not there yet. Not only is the navigation a big issue, but feeding enroute is a major challenge as well. Birds are known to stock up on body fat prior to their trip. Hummingbirds often increase their body fat by as much as 40 per cent, which they will lose – and more - along the way. Many species (geese are a good example) will feed along the way at established stopover locations along their flyway. Hummingbirds, being low daytime flyers during migration seem to feed as they move south in a wide front until they reach the Gulf of Mexico. Here, they either slip down the coast to Mexico or embark on a 500 mile straight shot over open water, lasting 20 hours or so of continuous flight.
Opportunities:
Being able to point out a hummingbird to scouts and telling them a little about the bird might be something that they have never experienced before. They probably won’t see one flying through their 6th grade classroom. It’s not too late this year to set up a feeder near your house to help them fatten up for their upcoming trip south. (Leave it up until early October.) See if you, or your scouts, can see the ruby throat. Next spring, get your feeder out by mid-April and see if you can make some new friends for the summer. Finding the recipe for the sugar solution on the internet is easy. Again, as a scout leader, expose your scouts to nature whenever and wherever you can. Maybe watching and learning about hummingbirds, a common and non-endangered species can be a positive experience for young people instead of constantly exposing them to stories of climate change, endangered species, deforestation, erosion and Lyme disease. Nature is always out there. Enjoy it. Teach it.
Thanks for reading NATURE NOTES. Reach out to me anytime at
Bob Garst
