The purple martin (Progne subis) is the largest species of swallow in North America. They are migratory birds that breed in North America and winter in South America. Purple martins rely on humans to provide nesting sites in the form of birdhouses or gourds. Over the past few decades, purple martin populations have declined across much of their breeding range. However, they remain common summer residents in parts of the eastern United States, including Virginia. Northern Virginia, located outside of Washington D.C., represents the northern edge of the purple martin’s breeding range on the East Coast. Let’s take a closer look at the status and distribution of purple martins in northern Virginia.
Range and Distribution
The purple martin has a very large breeding range that extends across most of North America east of the Rocky Mountains. Their breeding range stretches from central Canada south throughout most of the eastern United States and along the Pacific Coast. The core of their breeding range centers around the Mississippi River Valley. On the East Coast, purple martins breed from Maine to Florida. They are most abundant in the southeastern states and become less common further north.
In Virginia, purple martins can be found statewide during the summer breeding season. They are considered common summer residents in most parts of Virginia, according to the Virginia Department of Wildlife Resources. Their numbers tend to be highest in the southern and eastern parts of the state. In northern Virginia, purple martins occur locally at breeding sites but generally in smaller numbers than further south and east in Virginia. The handful of counties that encompass northern Virginia, such as Fairfax and Arlington Counties, mark the northern limits of regular breeding by purple martins in eastern Virginia.
Breeding Habitat Preferences
Purple martins show very strong preferences for open, rural areas that offer suitable nesting sites near open water. They tend to avoid heavily forested areas. Martins nest either in cavities in dead trees (natural sites) or in human-provided nest boxes. Over the past century, purple martins have become almost entirely dependent on man-made nest boxes in the eastern United States. The availability of suitable nesting sites largely determines their distribution and abundance.
In northern Virginia, purple martins are most likely to be found breeding in open agricultural areas or near rivers and lakes that provide nesting sites. Prime breeding habitat occurs along stretches of the Potomac River in northern Virginia where conditions are favorable. Martins frequently use nest boxes or gourds provided in yards of lakeside homes or at marinas. Given the suburban nature of much of northern Virginia today, martins are generally less common there than in more rural areas of the state further south. However, they will readily inhabit suitable sites provided with nest boxes, even in suburban neighborhoods.
Spring and Fall Migration
Purple martins are neotropical migrants that make a very long migration each spring and fall between their breeding range in North America and wintering grounds in South America. They spend their winters primarily in the Amazon Basin region of Brazil. The migration route used by East Coast martins takes them across the Gulf of Mexico and Central America.
In spring, purple martins first arrive back in Virginia in early to mid-March. Spring sightings are later further north, with first arrivals in northern Virginia typically in late March or early April. At this season, migrant purple martins can often be seen passing through northern Virginia in flocks foraging for insects overhead or resting briefly at backyard feeders. By late April, most martins have reached their breeding grounds and dispersal to nest sites occurs.
In fall, martins begin congregating into larger pre-migratory flocks in July and August. Their southbound migration from Virginia usually peaks in late August and September. However, some martins linger into October or even early November before migrating south. So fall migrating flocks are still possible in northern Virginia through late October, providing a last chance to see them before they disappear for the winter.
Population Status and Trends
Purple martins have undergone significant population declines in parts of their breeding range over the past few decades. Loss of natural nesting sites, competition from introduced species for nest cavities, and declining insect prey populations are likely contributing factors. Between 1966 and 2015, purple martins declined at an average rate of 1.3% per year across North America according to the North American Breeding Bird Survey. However, trends vary regionally.
In Virginia, purple martins are still considered common nesters, although their numbers have decreased statewide compared to historical levels. In northern Virginia, breeding populations appear sparse relative to other parts of Virginia, as martins are less common at the northern edge of their range. However, local populations may fluctuate or increase where nest boxes are made available. For example, a nest box program at Mason Neck State Park in Fairfax County has attracted up to 100 breeding pairs some years. Overall, purple martins remain present each summer in northern Virginia but careful conservation of nesting sites is needed to maintain their populations.
Conclusion
In summary, purple martins are present each summer breeding season in northern Virginia, which represents the northern limits of their breeding range on the East Coast. Suitable nesting sites, such as nest boxes and gourds provided by humans, are essential for attracting and maintaining martin populations in northern Virginia’s suburban landscape. While martins have declined in parts of their range, active conservation efforts focused on nest sites can help provide critical breeding habitat for purple martins in northern Virginia. So if you live in northern Virginia and want to host these beautiful swallows, be sure to put up some nest boxes! With appropriate housing, northern Virginians will continue to enjoy the aerial acrobatics and summer chatter of purple martins for years to come.
