Purple martin scouts began returning to Kentucky in late February this year but right now in the past few days, more reports are coming in of seeing purple martin scouts. So now is the time to get that martin box up and cleaned out and prepared for the birds this year.
While you still have some time to get a new house up and running, the only time you should open your nesting box early is if you see birds using a neighbors house that is within 1 mile of your property. Generally speaking you have about 4 - 5 weeks to get your house up and running after the first adult scouts arrive because the birds that will select a new housing location are sub-adult (last year's fledglings that have not yet nested) birds. Older or mature martins rarely, if ever, can be lured into moving to a new location because they have a strong nest site fidelity, which means nothing more than coming back to the same place they have nested in the past. In Martin culture, the oldest birds arrive first and the youngest arrive last and it occurs over a several month period with new birds arriving daily, but you should be prepared because if you want to attract a new colony of martins (and it can be difficult) now is the time to get things ready. Why is it so difficult to attract a new colony? The biggest and most common reason is that houses are placed in the yard incorrectly. These aerial acrobats can't tolerate trees that are as tall as the housing unit located within 40' and to be on the safe side it should be 60' from the housing unit. This spacing should be in three directions and as for the fourth direction, it should be from 40 to 120' from your house or building. It appears that martins have "learned" that housing units in close proximity to human habituation reduces predation (the likes of raccoons, snakes, hawks, owls, and crows) and the birds have a better chance of fledging more young. If you aren't getting martins nesting, try moving the housing unit closer to your home. Reason number three as to why folks don't get nesting martins is that the unit is not painted white. Why white? Well because it reflects the sun better and the birds don't experience as much heat stress, it creates a contrast with the dark entrance hole making it more enticing, and finally, male birds seem to prefer it for courtship. Another reason you don't attract martins is opening the unit too early and it gets invaded by house sparrows, finches, starlings, and other nest site competitors. If this happens you might never get martins to nest in that unit. This doesn't mean you shouldn't open the house before the birds arrive because if you wait until you actually see birds, it is too late. So open at least a few holes on each side prior to birds arriving and maintain vigilance to keep the other species out. For established colonies you can wait until you see birds returning because of their strong nest site fidelity. If you have vines, shrubs, or bushes growing up the pole, remove them as the birds rarely if ever nest where vines, and other plants crawl up the pole because the birds instinctively know it increases the chances of predation. In the same vein, do not put any guide wires or have the house located near ANY wires that are close enough for a predator to access the house and this means at least 10' which is about how far a squirrel can jump. Finally make sure the housing unit has the correct dimensions and while it may sound silly, there are varying recommendations as to what housing should look like. The most important feature of any housing unit is that the size should be no smaller than 6" x 6" although 7" x 12" is preferred, the entrance hole should be 1" above the floor, and the size of the hole should be 2 to 2 1/4." Lastly, the housing unit should be secured to a pole that can be raised and lowered by either a telescopic or pulley system so that pest birds can be evicted, units can be cleaned and closed/opened, and you can check on the baby birds to keep records of what is going on. Good luck in attracting these beautiful birds.
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