By Jon Friedman
Spring and early summer are the time of year when most hummingbirds migrate north from their winter ranges and late summer through fall months are when they migrate south to their winter ranges. In Arizona, we see it start in January when the Costa’s arrives. Black-chinned, Rufous, and Broad-tails come up in February. Broad-bills, Calliopes, and Blue-throats arrive in March. The rare Lucifer shows up in April. May brings the Violet-crowns and White-ears. Allen’s passes through in July. Anna’s take up residence in September, and stay around until mid-May.
When hummers return south, they do so in a similar, staggered manner. See the table at the end of this article for approximate arrival and departure times for our impressive list of hummingbirds that can be found in Arizona. You’ll see that we have hummingbirds in Southern Arizona year-round. Our hummers are here to breed and this also happens year-round.
Hummers do not migrate in large flocks as many other species do. While they migrate along familiar routes, they do so as individuals. Adult males will often arrive ahead of females and juveniles. Hummingbirds will follow blooming flowers northward out of Mexico in what researchers call the “nectar trail.” Nectar-producing flowers will begin flowering and producing nectar earlier in the more southern areas and later in the more northern areas. Hummingbirds time their migrations in tandem with the flowering schedule, much to their advantage.
Hummers take advantage of the timing sequences that nature provides to insure food sources all along their long journeys. They may spend only a few weeks or as much as a couple of months to complete their trips between summer and winter territories. They consume copious amounts of both nectar and insects along the way. Many of the insects they consume are found on and around the nectar-producing flowers they seek out.
Nectar provides them with the fuel they transform into quick energy and the insects provide them with the nutrition they need: vitamins, minerals, amino acids, protein, fiber, and fat. While the insects provide the nutrition they need in their everyday lives, nectar should be thought of not as food, but as energy. Think of your hummingbird feeders as refueling stations for these energy-needy birds – much as you understand that gasoline is the fuel that powers your vehicles.
Banding records indicate that the same hummingbirds follow the same routes each year. Apparently they learn the way as juveniles and don’t risk going a different, unproven way. Their brains act like mini-computers and remember the exact locations of the many nectar sources they have previously visited. This enables them to revisit nectar sources, both natural plants and feeders, and prevents them from wasting time and energy seeking out new sources.
Most hummers will prefer eating a natural and wild diet while migrating and in years when we have normal to better-than-normal rainfall. However, over the past few decades, we have been experiencing a worsening drought. Backyard birders are providing an important service for hummers when they supply fresh nectar daily. Assisting Mother Nature in lean times allows the hummers to not only survive – but to thrive!
This phenomena helps explain why we experience more hummers at certain times of the year and fewer at others. When you notice this happening in your backyard, we advise that you “keep the faith” and make sure that your feeder is stocked with fresh nectar even if fewer than normal hummers are present at your feeders. The birds will return to your feeders when natural nectar sources dry up. Planting native flowers and blooming cacti that hummingbirds prefer will also help attract them to your yard. A detailed list of preferred native Sonoran desert plants can be found in our birding articles archive at wildbirdsonline.com.
Sometimes migrating hummingbirds make stopovers along their long migration routes. Average layover time is from one to two weeks. If they find what they need in the spring, they may extend their stay into the summer. In the Tucson basin, if your hummer feeder is always stocked and ready to go, you have a better chance of keeping the hummers longer. Besides, hummingbird feeders can attract other nectivores at times. Orioles, bats, and butterflies are all known to use nectar feeders, and these animals need life-sustaining nectar as much as hummers do. As nature-lovers we always encourage feeding the wider range of nectivores.
Along with following the nectar corridor, or “nectar trail,” hummers also use tail winds to their advantage. The average speed of a migrating hummer in still air is 25 to 30 miles per hour. A good tail wind could double that speed. When tail winds are present on the southward migration of Ruby-throats through Texas, their numbers reported by birders dramatically increase. On the east coast, they often time their southern migration with the hurricane season in the Gulf of Mexico. A favorable tail wind could make their 600-mile journey across the gulf much easier.
Mature males invariably arrive before the females and young. One theory as to why this happens is based upon the high energy requirements of the hummers. Since a hummingbird may feed thousands of times a day, it cannot survive unless it is close to a food source. Migration forces hummers into unknown territory, where finding new food sources along the way is risky business. The males take on this difficult task. If a bird dies trying to find the next feeding source, the species loses only a male bird. On the other hand, if he is successful, his twinkling iridescent markings serve as a guide for the rest that will follow.
Before starting migration, hummingbirds are known to feed voraciously. Long-distance travel requires extra fuel. Observers in Georgia and Florida note that the Ruby-throated Hummingbirds begin to feed heavily on flowers and insects in the fall. They eat so much that they add 50% to their weight in the form of fat layers underneath their skin. The extra weight sustains them on the southward flight across the Gulf of Mexico well into Mexico and Costa Rica.
Hot air balloonists have reported seeing migrating hummers at altitudes above 200 feet. Crews working on shrimp boats have seen Ruby-throats skimming the waves 60 miles out into the Gulf of Mexico. They occasionally see sparrows that far from land as well. Off the west coast of Mexico above Puerto Vallarta, fishermen see hummers 50 to 75 miles out. Both balloon pilots and boat operators have hung hummingbird feeders on their vessels to aid the sometimes exhausted hummers.
The mountain ranges and rivers in the Americas lie roughly along a north and south Axis. It is possible that they act as guiding lines for hummingbird navigation. The continental divide provides a dependable source of flowers and insects for sustenance, as well as favorable winds in both spring and fall. The summer monsoons we experience in the Sonoran desert bring heavy rains to the mountains, allowing a second flower and insect bloom. This provides near perfect conditions for fall migration and brings in a great variety of hummingbirds.