Seven Advantages of the T-14 Wooden Purple Martin House
Ken Kostka
Purple Martin Preservation Alliance
Pittsburgh, PA

            In my 25 years of martineering, I have used just about every type of martin housing available - from metal houses to plastic gourds - but one type of housing stands out and has become my favorite: the wooden T-14. The "T" refers to the name of the designer, Andy Troyer, an Amish ropemaker who has grown one of the largest colonies of martins in Pennsylvania - 150 breeding pairs. The "14" refers to the number of compartments in the house.  Before I get to the seven advantages of the T-14, let me state that it has the two basic design features that ANY type of martin housing system SHOULD have for proper management and maximum potential breeding success: A) it raises and lowers vertically (without tipping over or requiring a ladder) to allow for trapping or removal of non-native pests species, and B) the nesting cavities can be easily accessed to allow for nest monitoring (without damaging the nest). This article also assumes that the T-14 is equipped with slide out nest trays, an optional feature that I highly recommend.

What follows are, in my opinion, the 7 advantages that the T-14 has over other types of acceptable martin housing. Please keep in mind that these are in some cases only slight advantages. There are many types of other fine martin housing available.

#1 The Dryness Factor. The T-14 is the only type of housing in which the nest stays totally dry, even in driving, prolonged rains. This can be attributed to the fact that the compartments are very deep, horizontally, and have individual porches that do not trap or collect rain, as some metal and plastic houses with shared porches do. Nor are there any hanging holes, as with most gourds, through which water can gradually seep in. Additionally, some two-piece snap-together or screw-together gourds have a seam that allows water to seep in. Wet nests are bad news. The moisture creates the perfect environment for nest parasites like blowfly larvea, mites, and fleas - all of which feed off of the blood of the nestlings.

#2 The Stability Factor. Unlike gourds or lightweight plastic/aluminum housing, the T-14, is thick, solid, sturdily mounted, and therefore relatively unshakeable. This makes it more impervious to predators, in my opinion. Gourds can be shaken by owls that grab the entrance hole and hang on or that land on the support arm and are able to get behind the guards blocking the entrance hole. Thin-shelled natural gourds can even be broken by owls, as can flimsy plastic or aluminum housing. The T-14's weight and sturdy mounting (either a wooden 4" x 6" or a 3" x 3" high quality metal pole) also allow it to stand up to high winds. Some metal and plastic houses tend to be more easily toppled by high winds because of their lightweight poles. I never worry about the T-14 in a windstorm.

#3 The Insulation Factor.  Wood is a great insulator, and the T-14 is made of 3/4" thick wood. It stays warmer in cold weather and cooler in hot weather than does metal or plastic. And even a few degrees can be the difference between life and death for adults during prolonged periods of very cold weather - or for nestlings during periods of extreme heat.

#4 The Nest Maintenance factor.  It's extremely efficient and convenient to do nest checks and changes in a T-14 equipped with nest trays. The nest tray simply slides out, nest and all, allowing for close-up and unobstructed inspection of the nest, eggs, or nestlings. In houses without nest trays, as with gourds, you must inspect the nest through an opening that restricts your view in distance, angle, and light level. Think of the T-14 nest tray system as somewhat like a chest of drawers. Imagine how much harder it would be to find and get at your clothing if the front opened but the drawers didn't slide out. It's also easier to do nest changes or treatments with the slide-out trays.

#5 The Entrance Hole Changeability Factor. In the past few years, there has been a revolution in entrance hole design. Landlords must choose from a variety of entrance hole styles - from round to obround to crescent to Excluder to Conley to Excluder II. The T-14 is one of the easiest types of housing to change entrance holes on. Once a 3" x 4" square hole is cut above the porch, a plate containing the desired entrance hole can be secured simply using 2-4 small sheet metal screws. Plates can be switched at any time with a few turns of a screwdriver. Most gourds come with one type of entrance hole stamped in, and changing it is usually a rather involved process that often cannot be completed in mid-season.

#6 The Variety and Economy Factor. Not only is it possible to have several different types of entrance holes, but the T-14 is perfect for hanging gourds under, giving martins a choice of housing without needing to erect another pole. I once attracted a pair of martins to a T-14 compartment, but they eventually ended up nesting in a gourd hung underneath. A set of T-14 gourd-hanging brackets holds up to 4 gourds, and an additional gourd can be hung under each of the four sections, for a total of eight. These eight gourds are symmetrically arranged and all at the same level.  They come down with the house and are easily accessed. It's sort of like having a wooden house and gourd rack in one.

#7 The Attractiveness Factor. When people ask me what type of material for martin housing I recommend, I ask them whether they would rather live in a house made of plastic, metal, or wood, and I always get the same answer. Aside from wood's insulation value (as described above in #3), keep in mind that martins originally nested in old woodpecker holes and other tree crevices, such as rot pockets. Indians sparked a tradition shift by supplying martins with natural gourds, which are a wood-like material.  Colonists furthered the tradition shift by supplying wooden houses. While martins nested in tree cavities for thousands of years (and still do out west), it is only in the past 50 years that martins have been offered plastic and metal houses, and I still believe that, overall, they prefer wood, and that offering a manageable wooden house with gourds hung underneath gives you the best chance of attracting martins and growing a colony, especially if you live in an area of martin scarcity. I attracted martins to two different  locations in an area of martin scarcity using T-14's over the past six years. No other housing worked in over 20 years of trying in that area.  I also built up a dwindling colony from 8-10 pairs to 28 pairs in three years after installing two T-14's. (100% occupancy)

    Once again, manageability is the single most important factor when it comes to martin housing. It is better to have a manageable aluminum house rather than an unmanageable wooden house.  Also, ALL housing should have both climbing animal guards, sometimes called pole guards, to protect against raccoon, snakes, and squirrels as well as owl guards to protect against owl, hawks, crows, and gulls. And any house or gourd rack should raise and lower vertically, without tipping over or requiring a ladder, to allow for trapping or removal of non-native pests species, and for easy inspection of the nesting cavities.

    Finally, a word about cost. Some may argue that the T-14 is expensive and therefore impractical for the beginning martin hobbyist, who isn't even sure he or she can attract martins. Let me point out that this notion of buying inexpensive housing to avoid making a big investment because one may not attract martins can become a self-fulfilling prophecy. However, there are many types of acceptable martin housing available. Some are better than others. In the end, the landlord will have to draw his own conclusions.