By Kristen Currie
What to watch for in February: Purple Martins and Open Country Birds
Is Spring on its way? Purple Martins, our largest swallows, seem to think so. These swallows spend the winter in South America and now the earliest migrants have begun returning to North America to breed. They have already been recorded in Florida, Georgia and Alabama. By the time you read this, it is very likely some will have been seen in Texas too. What drives these adult birds to risk their lives returning in February which can have some of central Texas’ worst winter weather? These birds want to get the nest sites most attractive to females. If they arrive too early, starvation and hypothermia are real possibilities. If the weather cooperates, they get a jump on nesting so their offspring will have a longer time to mature before they migrate south again.
Let’s look at a timeline for arriving Purple Martins. Adult males and some adult females, born in 2020 or earlier, start arriving on the Upper Texas Coast in late January, and in much of Texas between February 1 and February 15. Subadult birds, those that were born last year, don’t arrive until 4 to 12 weeks later. Once the birds arrive they need 4 to 6 weeks to recover from their journey before they start nest building. Nest building can take another 3 to 4 weeks. If you have friends in the northern states, they have much longer to wait before “their Martins” arrive. For example the Great Lakes area Purple Martins won’t arrive there until mid to late April.
Fun Facts about Purple Martins
- They are highly social birds. It’s rare to see just one. They nest in colonies, using gourds or other housing units provided by humans. They form large pre-migratory roosts in late summer before heading south.
- At the nest colony, the birds will often fly up over the colony as a group to attack potential predators such as hawks, gulls or Blue Jays. Together they will chase the predator out of the area, swooping just above them but rarely making contact. Cats and dogs are on the hit list too. Purple Martins may abandon a colony if a Great Horned Owl discovers it.
- Purple Martins get their name from the appearance of the adult males which are iridescent purplish blue over their entire bodies. The adult females and subadult birds have variable amounts of purple, but look grayish below.
- It took about 3 weeks for one Purple Martin to travel 5000 miles from Brazil to Pennsylvania.
- Purple Martins eat flying insects – they are called aerial insectivores, catching insects in flight, and are dependent on insects year round.
- They drink water in flight, too. The Triangle Pond is a good place to watch them skimming along the water’s surface, scooping up water with their lower bills.
- A study from the University of Oklahoma found that Purple Martins eat a lot of fire ants. When a fire ant colony is ready to reproduce, it sends winged queens and males off into the air to mate and then found new colonies. Purple Martins take advantage of this bounty, and feed them to their young.
- There are several Purple Martin colonies in Austin. The most well-known is at the Hornsby Bend Biosolids Management Plant’s Center for Environmental Research. Another is by the covered gazebo on the south end of the Mills Pond Recreation Area near Doria Drive in north Austin. There is one at the Balcones Canyonland National Wildlife Refuge headquarters too. These are sustainable colonies due to motivated groups of volunteers who maintain them, taking the gourds down over the winter, cleaning them and raising them in January, then managing and monitoring them throughout the breeding season, removing sparrow and starling nests. A colony would be a wonderful community-building addition to a park near you! It does require a commitment, as the birds have tremendous site fidelity, returning to the area where they were born, or had nesting success before.
Take a Drive in the Country
February is a good time of year to visit Northeast Travis County, where agricultural land still exists. There you can often see a few long-winged raptors, sporting white rumps, flying low over the fields. These are Northern Harriers looking and listening for prey such as small rodents. They have a facial disc similar to owls that helps amplify sounds. Adult males are studies in white and gray with the nickname “Gray Ghosts.” Another bird seen there reliably during the winter months is the Loggerhead Shrike, the subject of our February member meeting. Shrikes make use of utility lines to scan for prey, before dropping down to pounce on them. The Loggerhead Shrike has the nickname, “Butcher Bird” due to its habit of stashing prey for future consumption on thorns and barbed wire. This distinctive black, white and gray songbird with a hooked bill is about the size of, and frequently mistaken for a Northern Mockingbird.