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Purple Martins

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Martin Migration Madness!

Male and Female Purple Martins Male and Female Purple Martins image © Greg Lavaty

Peak numbers for Purple Martins occur in July and August when Purple Martins form large flocks and roost together in great numbers in preparation to migration. Some roosts may have thousands of birds. When the birds arrive to roost in the evening, it can be an amazing spectacle with the sky literally black with martins! If you know of a large roost, please contact us at birds@houstonaudubon.org. We have prepared this informational flyer about communal roosts, suitable for display. Join us in helping to protect Purple Martins!

Summer, 2014

Purple Martin Watch Parties: Houston Audubon will host three Purple Martin Watch Parties this summer: on July 25 and August 8 we will meet at Stafford and on August 2 we will be at Willowbrook Mall. See directions below for Stafford. At Willowbrook Mall the martins use the oak trees located on the north side of FM 1960 (7606 FM 1960 Rd W, Houston, TX 77070 Map). We meet in the parking lot behind Starbucks.
(Photos & Videos of the Stafford Martin Party on July 26 by Mary Anne Weber).
(Photos and Videos of the Willowbrook party on August 2 by Mary Anne Weber).

Purple Martins in the News: Summer 2013

Traditional Locations of Large Martin Roosts

  • Stafford: The Fountains is a shopping center in Stafford at Hwy 59 and Kirkwood. If you take 59 south, exit Kirkwood and turn right onto Fountain Lake Drive. Turn left into the shopping center. The martins congregate at Gordon Park behind the center. They drink at the ponds and then perch in the trees and wires at the park and around the shopping center. The park is on Fountain Lake Drive directly behind the shopping center. In 2011, huge numbers continued through late August. The image at the right was taken at Stafford. In 2012, Thomas Bumby and Patrick Dusek confirmed martins were roosting at the Stafford site on June 2-3. Donald Troha located the martin roost on weather radar as early as June 8 and on the evening of June 13 counted 3,000 birds.
    Purple Martins in Stafford: June 23, 2012 by Mary Anne Weber
    Video of Purple Martins at the roost in Stafford: June 23, 2012 by Donald Troha

  • Willowbrook Mall: Large martin roosts are found around the mall. (Video by Mary Anne Weber, July 23, 2012). (Photos by Mary Anne Weber, July 23). (Video by Donald Troha) On July 14, 2012, thousands of birds were on the north side of 249 in the evening. In the summer of 2010, known large roosts included the KBR building on Clinton Drive in Houston and The Willowbrook Mall in north Houston. The KBR Building had about 15,000-25,000 martins in early July, and the numbers were at least as high at Willowbrook. At Willowbrook the martins usually settled in just 4 or 5 oak trees: two oaks right between the street FM 1960 and Starbucks and the other two oaks closer to the Room Store along the drive going up to the front of the Room Store.

Radar Sightings

Purple Martin flight patterns are sometimes visible on weather surveillance radar. The patterns can resemble rings which are particularly dense as they disperse to forage in the early morning.

About Purple Martins

Family: (Hirundinidae ) Swallows and Martins

Preferred Habitat: Meadows and fields

Seasonal Occurrence: Common spring through fall. Nests in our area.

Profile: The Purple Martin is the largest North American swallow. Adult males are purplish-black and darker on the wings and tail. Females and immatures have dusky throats, light bellies, and dull purplish-black upperparts. Martins feed mainly on day-flying insects, including beetles, wasps, dragonflies and mosquitoes. Martins do not use feeders but are known to appreciate crushed bits of eggshell put out on a flat surface. Purple Martins are quite common in Houston’s suburbs and rural areas.

The first martins arrive in Houston generally in mid-January. The scouts, who are primarily older males, come first followed by younger males and then the females. Nesting activities start in February. Both sexes build a nest composed of grass, leaves, twigs and other convenient materials such as paper and string. Four to five slight glossy white eggs are laid from mid-April through May. Incubation takes 15-20 days. Females do most of the incubating, while males assist in feeding duties. The young remain in the nest for 24-28 days. Families stay together for 3 weeks afterwards. Martins are generally single-brooded unless no chicks survive. In July and August, Purple Martins congregate in large flocks before departing south in the fall, forming communal roosts in the evening. All Purple Martins winter in South America.

Male Purple Martin Male Purple Martin image © Greg Lavaty

Martin Houses: Martin houses are very effective in attracting martins. The ideal martin house should be lightweight, cool, attractive, durable and resistant to parasites. The exterior color should be white to reflect heat. It should have guard rails to protect young birds and bright interiors to discourage starlings. The best compartment size is 6" x 6" x 6" with the hole 2 1/8" in diameter. The house should have good ventilation and drainage with sub-floors to discourage mites. A good way to discourage parasites is to scatter 1 tablespoon of powdered sulfur in each compartment just prior to nesting. Martin houses should be located in an open area with at least 15 feet clearance from trees and buildings. The pole should be 12 to 20 feet in height, with some sort of mechanism to lower the house for cleaning. Poles should be equipped with predator guards to protect against cats, squirrels, raccoons and other nest-robbers. To discourage house sparrows, keep the compartments cleaned of nest material before the martins arrive. In addition, door plugs should be used on the compartments in the off season.

Gourds: Gourds, both natural and plastic, make excellent housing for martins. Research has shown that martins using properly prepared and mounted gourds have higher reproductive success than with conventional houses. The fact they swing is something martins like and predators don't. Also their shape discourages predators. New plastic gourds snap together to make cleaning easy. Gourds attached to the bottom of regular houses may increase your chances of attracting martins.

More information on Purple Martins:


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