John Jay---Surviving Vandals, House Sparrows, and Starlings


Hosting Purple Martins has not been without hazards. An early problem that surfaced was vandalism. More than 3,000 students attend school on our campus, a few are liable to create problems.

One problem was students shaking the poles out of curiousity or to see the martins fly, a behavior which can disrupt the nests inside the gourd. Another problem was students on campus after hours climbing the aluminum poles, resulting in the collapse of the gourd set.

Both these problems were solved by the practice of affixing a 10 ft length of PVC electical conduit pipe, split lengthwise, around the gourd poles and holding the pipe halves in place with hose clamps.

A heavy layer of vaseline is then applied to these pipe halves, discouraging physical contact by the students while at the same time not ruining clothing in case of accidental contact.


Along with vandals, the most serious threat to our Purple Martins has been the European Starling. Starlings are martin-sized birds that resemble a mature male Purple Martin to the novice observer. The easiest way to distinguish them is by the beak: Martins have short, dark beaks whereas that of the starling in the breeding season is long, pointed and yellow.

Starlings are not native to this continent, having been introduced from Europe, and martins have few defenses against them.

The threat starlings pose to martins is that they also nest in the same sort of cavities that appeal to martins and will fight with martins for possession of them. Unfortunately in such a fight the martin invariably comes out on the losing side. The short, soft beak of the martin is no match for the long pointed beak of the starling. Adult martins are frequently killed outright or mortally maimed in fights with starlings. The martin at right was recovered dead from inside a gourd.

Starlings may invade the nest at any time, killing any young or adult martins and breaking any eggs that may be present.

A starling nest can be readily identified as starlings fill the whole cavity with dried grass and straw whereas a martin nest consists of a flat layer of dried grass and dead leaves on the bottom of the cavity, leaving the rest of the cavity open. Starling eggs are robin's-egg blue in color, those of the martin are pale white.

Note the starling nest material spilling out of the gourd in the photo at left. A pair of starlings invaded a gourd, evicted or killed the resident martin pair, built a nest and laid these six eggs in the space of about eight days.

Starlings MUST be controlled in order to keep a viable martin colony. Fortunately an easy and quite effective way is through the use of Starling Resistant Entry Holes (SREH). These oddly-shaped entrances capitalize on the fact that a starling usually has a deeper breastbone and longer legs than does a Purple Martin. The design of these entrances make it more difficult for starlings to enter.

A variety of SREH designs are available, pictured at is a bat-shaped Excluder entrance and a crescent.

.........................House Sparrows

Like starlings, the House Sparrow is not a native of this continent but was also introduced from Europe. Unfortunately for the Purple Martin, House Sparrows also nest in cavities. House Sparrows are small, brown birds common around human habitations. At right is pictured a male, showing the distinctive black bib.

While a House Sparrow is not the threat to an adult martin that a starling is, adult martins occasionally injured in fights with sparrows.


A more serious threat posed by House Sparrows is their habit of entering the nest while the adult martins are away and destroying the eggs and young.

Once in possession of a cavity, House Sparrows will rapidly fill the whole cavity with straw and dead grass, making it impossible for martins to enter. At right is pictured a female House Sparrow leaving a gourd.

Because they are smaller than martins, House Sparrows cannot be excluded by the design of the entrance.



Invading house sparrows, like those few starlings which succeed in entering SREH entrances, must be trapped and removed.

Fortunately a variety of traps are available on the market. Pictured here is a Natureline gourd equipped with a trapdoor entrance. In this case the entrance has been shimmed down to a size that will admit sparrows but exclude Purple Martins from entering the trap.

A more thorough discussion of these pests can be found at the Purple Martin Conservation Association website.

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