Another important consideration is predation. We recommend single pole structures with a platform on top, on mainland areas and any area where raccoons and other predators are present. Single poles are easily outfitted with a predator guard (inverted cone, or a sleeve of aluminum flashing) that prevent raccoons from climbing into the nest. A raccoon has been seen climbing into a 30-foot high nest, so a guard is very necessary on most nests.

An attractive nest, to an Osprey, includes a nearby perch. The male prefers to perch either on the nest or within 20-40 feet. A 2x4 that rises two to three feet higher on one corner of the nest structure is ideal, as is a perch pole of equal or greater height to the nest, placed nearby.

Ospreys generally return to New Jersey in late March, and take up nesting in April. Nest structures should be in place by mid-March for that season's use. Ospreys are most sensitive to disturbance during April, when they are laying eggs, and are most likely to abandon the nest if disturbance is too great. They will grow more defensive of the nest area in May and June when they have chicks, and both male and female must feed intensively to keep up with all the appetites. It is important that disturbance remain low during this time as well.

Ospreys have exhibited tolerance of certain types of disturbance, such as boat traffic on waterways, as long as such traffic ignores them. Disturbance increases as boats stop nearby and people focus on the birds at close range. A safe distance from which to observe ospreys will vary depending on the area, but observers must stay beyond the distance at which the adults react. Their reaction must be judged as even their attention to the observer, not simply when they lift off the nest in defense.

Finally, if you put up an osprey nest structure, please send a map location to the Endangered and Nongame Species Program at 2201 Route 631, Woodbine, NJ 08270. We include all potential nest sites in our biennial survey of ospreys in the state. If the nest is used by ospreys, please notify us.

Osprey Nest Platform Plans (pdf, 34kb)
Osprey Nest Platform Materials List (pdf, 7kb)