I was recently asked about when to take down hummingbird feeders. My answer was, “it depends.” But, thinking that was not probably a very scientific answer, I thought I would read up on the fall migration. Each hummingbird species has its own migration strategy, and it is incorrect to think of "hummingbirds" as a single type of animal. So that being said, the below information refers to the ruby-throated hummingbird (Archilochus colubris) or RTH for this missive.
Why do RTHs migrate? Being a migratory bird, hummers evolved to their present forms during the last ice age. As the ice retreated, these tropical birds expanded their ranges for food and nesting areas. In the fall the urge to migrate is triggered by the shortening length of daylight as autumn approaches. And, since hummers are carnivores (nectar being the fuel to power their insect catching activity); they need to migrate before fuel sources run out. And, we all know insects and nectar producing flowers are not abundant in subfreezing weather!
Weighing just over 3 grams, this tiny bird is a minuscule bundle of feathers and sheer stamina. A RHT weighs about 1/3 the weight of a common ballpoint pen. A migrating RTH will gain an extra 25-40% body weight for the trip. Needless to say the little birds are fat!
For a newly hatched hummer, there is no map or memory of past migrations. New hummers only have an urge to get fat, fly in a particular direction for certain amount of time and look for a good place to spend winter. (I would compare this to someone in my family who doesn’t ask for directions.) The birds will take the same path that was imprinted the first year they flew and will retrace that path every year as long as it lives. Plus the little guys fly alone.
All hummingbird migration involves admirable feats of travel, but the RTH’s journey is amazing. There are four common routes. Many RTHs come down and fly directly across the Gulf of Mexico which is an 18 hour trip for the birds. Others take a western route through Texas into Mexico directly. Some reach the Gulf coast and turn west and travel along the coast. And, then there are those that circle east and island hop to Mexico.
We Texans have it best though. The first week in September when tens of thousands of hummers start showing up for the staging of their trip across the Gulf, the folks of Rockport and Fulton host a Hummingbird Celebration! http://www.rockporthummingbird.com/ Here you will find the largest concentration of RTHs anywhere preparing for their departure. There are many educational exhibits and tours but the best is the backyard tours.
So it is not necessary to take down your feeders to force hummers to migrate. The birds that are at our feeders now are already migrating. If you remove your feeders, RHTs will find food sources elsewhere but they may not bother to return to your feeders next year.
Cornell University FeederWatchers program report hummingbirds being seen in Texas, Louisiana, Alabama, Mississippi and Florida December – February. Mark Klym, information specialist for TPWD who I met through the Texas Master Naturalist program, says Texas has a consistent number of wintering hummers. Several species overwinter along the Gulf Coast with some wandering even farther inland.Check out his book, Hummingbirds of Texas.
So I guess my answer still remains “it depends.”