Accessing Single Nestboxes Mounted on Marine Pilings, Upland Poles, or Other Existing Structures. --Stan Kostka, Western Purple Martin Working Group, e-mail: email@example.com
On a cool and breezy morning in May of 2000, while checking Purple Martin nestboxes on abandoned pilings in an intertidal area of Puget Sound during a low tide, I nearly fell from a muddy aluminum extension ladder while working at a nestbox nearly twenty feet high. As I stared down into the black mud where my now soiled field notebook lay, I realized that if I was going to continue gathering reproductive data and begin banding these birds, I needed a more efficient way to access the nestboxes. Using a ladder not only added considerable time and labor to the project, doing it in combination with slick mud added an element of objective danger that I could no longer disregard. In addition to the possibility that I could fall from the ladder, there also was the potential for some of these old unstable pilings to fall over while I was checking the nestboxes. In fact, that same day I had decided not to check another active martin nestbox nearby on a very old and unstable piling, out of concern that the piling would fall over under the weight of myself on the ladder leaning against it. So, not only did using the ladder require considerable extra effort and time, it created some objective dangers for me, and was reducing the number of nest checks and subsequent banding I was willing to attempt out of concern for the safety of the nesting birds. There had to be a better way.
The obvious solution was to be able to lower the nestboxes in a way that would not endanger nests with eggs or young, a technique used in many managed martin colonies east of the Rocky Mountains. There, martins nest almost entirely in multi-compartment ďmartin housesĒ or gourd clusters, some of which can be lowered using winches or other mechanisms, while keeping the nesting cavities upright. This method works well when multiple pairs of martins nest on one pole. However, I was working with many single wooden nestboxes on individual poles (pilings), spread out over several hundred feet of an intertidal mudflat, an arrangement common to the Northwest, since the beginnings of Purple Martin recovery efforts using nestboxes in the late 1970s and early 1980s. Multiple winches attached to pilings would be too expensive, less than secure in a public area, and be short lived in this saltwater environment. All the pilings spent half the time standing in saltwater, often up to nearly eight feet in depth.
After experimenting with pivoting nestboxes attached to new secondary poles attached to the existing pilings, I finally arrived at a most simple solution, in which the nestboxes are hung on the pilings much like a picture is hung on a wall. A ladder is still needed, but only for the initial installation on an existing pole, piling, or structure. Afterwards, all that is necessary to lower and raise the individual nestboxes is a length of 1 x 2. Here is how it works.
This method works quite well for single nestboxes mounted on poles anywhere.
Nestboxes to be accessed in this manner need to have some special features, but just about any single nestbox can be retrofitted to work. There are three needed features.
First, the back wall of the nestbox must be extended down below the floor some distance, at least a foot. 16 inches works for me, but longer may be necessary depending on how tall you are, and how high the nestboxes are hung, from where you will be standing when you access them. I now build all nestboxes using a 24 inch long piece of wood, 3/4 inch thick, for the back so that it extends down below the floor about 16 inches. If you already have some nestboxes, simply add a piece of wood to the back to extend it down below the floor. The extension does not need to be the full width of the back of the box, but needs to be 5 inches wide a few inches below the floor of the nestbox, and down lower only needs to act as a handle.
Next, get some large conduit clamps (1 and 1/4 inch works well). Be sure to get the type of clamp that uses two screws, one screw on each end of the clamp. Best to get some heavy gauge rigid ones, and some lighter ones that can be bent more easily. Each nestbox will require two clamps, one heavy rigid one, and one lighter one that can be more easily bent. Also, get some 2 inch hardened deck screws, two for each rigid clamp, and some 1-inch screws, two for each lighter gauge clamp. Also, get some large common nails, five or six inches long having a diameter of about 1/4 inch, one nail for each nestbox.
Attach one of the large rigid conduit clamps, centered at the back edge of the top of the nestbox, parallel to the back wall. The nestbox will hang on this clamp, so use long 2 inch hardened deck screws that go firmly into the back wall. Then, attach another conduit clamp, this time one of the lighter ones, slightly flattened so that it will accept a 1 x 2, three inches below the floor, centered on the front of the extended back wall, parallel to the floor, using the shorter screws. The function of this low clamp will be to accept the 1 x 2 so the nestbox can be raised and lowered without needing a ladder.
How high you will be able to place a nestbox accessed in this manner will depend primarily on how tall you are. I am over 6 feet tall, and using an eight foot long piece of 1 x 2, I am able to hang these nestboxes (with the back wall extended down 16 inches) up to a height of 15 feet. Some reasonably good upper body strength along with good hand-eye coordination will give you an advantage. But in the end, a little practice and perseverance will carry the day.
Here is how you decide how high you can hang the nestboxes. Hold up a nestbox over your head, keeping it level as if it had a nest containing eggs, maybe letting it tip back slightly. Hold it by the back below the floor. While continuing to hold the nestbox up there with one hand, take the 1 x 2 in your other hand, and put the end of the 1 x 2 into the conduit clamp on the bottom rear of the nestbox. The nestbox will lean forward slightly and hang on the 1 x 2. If you cannot get the 1 x 2 into the bottom clamp while holding the nestbox relatively level, or tipping it back just a bit, you will need to shorten the length of 1 x 2, or lengthen the back of the nestbox so you can hold it higher. Once you have the nestbox up on this piece of 1 x 2, raise the nestbox up as high as you can using both hands on the 1 x 2 and make a note of how high the roof of the nestbox is above where you are standing. This is the maximum height at which you will drive the large common nail into the post or piling.
Now you are ready to install the nestboxes. Start by climbing the ladder (hopefully for the last time at each nestbox) and driving a large nail into the piling at the desired height for the roof of the nestbox. Drive the spike so that it slopes upward out of the piling, and leave at least two inches or more sticking out. Climb down and remove the ladder. Raise a nestbox using the previously described technique and hang it on the large nail. Repeat this procedure until you are comfortable doing it, and realize it will be somewhat more difficult under windy conditions.
Practice raising and lowering the nestboxes until you feel comfortable. Once a box has a clutch of eggs, there is no room for error. Drop a box with eggs, or spill them out of the nestcup, and that will be the end of that nest.
There will be many variables when dealing with pilings at different sites, and here are some of the ones that Iíve dealt with.
At windy sites, the nestboxes will need to be secured. Attach a length of cord or wire to the bottom of the extended back wall, and once the box is hung, tie off the cord or wire to another smaller nail in the piling, down at a level you can reach without a ladder. Depending on how the boxes are oriented to the wind, they may tend to rock back and forth too much. If this happens, nail a vertical strip of wood along side the hanging nail to create a flat spot on an otherwise round piling down the length of the extended back of the nestbox. This flat spot, in combination with the nestbox being tied off to a lower nail, should prevent most movement of the box. It is not necessary that the box hangs completely still at all times. Remember, martins nest in gourds that move in the wind. You just donít want them to be rocking in the wind too much, an action that could addle some eggs.
Although Iíve never tried it yet, another way to keep nestboxes from rocking in the wind and make them more stable would be to use two conduit clamps on the back edge of the roof of the box and two nails in the piling. The space required to put two clamps in line would require the use of smaller clamps, or a larger box, in either case, adding to the difficulty of the raising and lowering procedure. The lighter the box, the easier it is to get up there and get it on that nail.
For pilings in an advanced state of decay, that wont hold a large hanging nail very well, use a piece of 2 by 6 (or 2 by 4) as long as the extended back of the nestbox, put the hanging nail into this 2 x 6, and then attach the 2 x 6 vertically to the piling (hanging nail at the top) with multiple smaller nails or screws, and with wires wrapped around the piling if necessary. Pre-drill the 2 x 6 to prevent it from splitting when you place the large hanging nail. This flat 2 x 6 surface will also keep the nestbox from rocking back and forth in the wind on an otherwise round piling, and lately Iíve been putting up pieces of 2 x 6 behind all new nestboxes, whether the piling is rotten or not.
For pilings or other existing poles (like fence posts) that are too short, use a longer piece of 2 x 6, (or 2 x 4) as an extension to get the nestboxes high enough, or well above the highest tide that will occur during the nesting season. In this case, or where you are installing new poles or extensions, put the hanging nail into the pole or extension before it is raised, and there is then no need for a ladder.
So there you have it. This description may sound a bit complicated, but the process is really quite simple. Please let me know how this system works for you and if you have any questions, or ideas on how to improve it.
PS. The problem with any innovation is that it leaves what you did before somehow lacking. Now I need to get out to the nestbox colonies that are accessible only by boat at high tide, and retrofit them for ladder-less access as well, so I will be able to access those nestboxes at less than a high tide, without climbing a ladder out of the boat.