Long after the sun sets and the city has fallen asleep, the darkened skies over Houston fill with billions of birds silently on their spring and fall migration. Ruby and emerald jewel-toned hummingbirds flit between flowers, rose-pink spoonbills wade by the coast, and warblers of every color bounce among the trees. Many of these birds have been flying for nearly twenty-four hours straight by the time they come to Houston to rest and recover so they can continue their journey north.
Migration is a complex process that can change in intensity and timing each year, but the reason for it is virtually the same. Houston Arboretum and Nature Center Naturalist Kelsey Low states, “For migratory birds in North America, most travel north to take advantage of longer summer daylight hours and low competition during the nesting season … However, most birds must leave the north when it gets cold because their food, usually insects or plants, are killed off by snow and ice, and so they travel south where it is warm in the winter.”
This explains why there are two main bird migration windows in North America: spring migration, which spans from about March to May, and fall migration from September to November. The spring migration season has recently started for Houston, with the peak coming from mid to late April.
Houston as a city has proved to be a very important piece in the spring bird migration event.
Different birds take different routes called flyways when migrating. Wyatt Engelhoff, a Sanctuary Manager at Houston Audubon, says that flyways are “a path (defined by geological features) taken by a lot of different species of birds during the course of a year.” Houston is under the Central Flyway, which “encompasses the swath of land between the eastern foothills of the Rocky Mountains, east to about the Mississippi River,” Engelhoff says.
Engelhoff further explains that “This Flyway conveys billions of birds representing over 350 species from Central and South America through to the Great Plains, boreal forests, and high Arctic. There are a lot of different habitats present along this flyway, from cypress forest and saltmarsh on the Gulf Coast, short and tallgrass prairie and wetlands, spruce forest, and Arctic tundra. This Flyway is important because it connects so many different species to different habitats.”
Contrary to popular belief, many songbird species do most of their traveling overnight, and there are a few reasons why.
“Nocturnal migration allows smaller species to escape detection from possible predators,” Engelhoff says. “It also helps to keep them cool. Birds have higher metabolisms than most mammals, which generates a lot of body heat. This means birds can overheat if they fly continuously on a hot day.”
Due to our critical location during migration season and the fact that many birds travel at night, Houstonians can help and protect birds during their migration. Low says one thing people can do is to take off their house lights at night, which can prevent window collisions by birds.
“Most birds [who travel at night], get really confused by artificial lights and may kill themselves by flying into lit-up windows.”
Another thing people can do that will help birds in the daytime is to put stickers or decals on their house’s windows to prevent daytime collisions.
“You can use exterior blinds, lots of vinyl window decals, temporary paint, even soap – anything to mark up the outside of windows,” says Low.
In addition to these measures, Houstonians can also plant native plants in their backyards that feed and shelter birds, such as Turk’s cap and coneflowers. They can also feed birds and provide water sources, such as birdbaths, for them.
CVHS also has proved to play a part in bird migrations through Houston. “I have seen some warblers in the trees near the [CVHS] campus. I believe they were yellow-rumped warblers, which start [migration] in the winter and migrate all the way up to Canada for the summer,” says CVHS senior and President of ECO Club, Justin Leahy.
He said he has also seen a type of migratory hawk, called the broad-shouldered hawk, around CVHS as well. “They start [migration] in Central and South America and then migrate up to the northern US and Canada in the summer,” Leahy says.
Besides those mentioned above, there are many other interesting species of birds that almost anyone can find in the city during migration season. Low says some easy birds to look out for are American robins, northern cardinals, red-winged blackbirds, and Baltimore orioles. For more experienced birders, Engelhoff mentions being able to see rarer waterbirds, such as roseate spoonbills and many species of colorful warblers.
Some good places near the city center to see migratory songbirds and waterbirds are the Houston Arboretum and Nature Center, Memorial Park, and Hermann Park. For those willing to venture a little further from the city, High Island near Galveston and Brazos Bend State Park in Needville are both excellent places to spot rarer migrants.
“While most of the birds we see in spring only spend a few days here (which makes up only a tiny fraction of their lives), in many ways it is the most important stop on their annual journey. If we do not have habitat for them here, they will not make it further north … That is why safeguarding sites for them along the way is an important part of protecting migratory bird species,” says Engelhoff.
