Plans for building osprey nest platforms

The following is an excerpt from Enhancing Raptor Populations – A Techniques Manual, published by The Peregrine Fund. The book is available for purchase in our online store.

Raptors that use open nests can also be induced to use artificial nests for the purpose of augmenting their populations. A number of these species have suffered declining populations at least partly due to loss of nesting places. Ospreys (Pandion haliaetus) received the most attention in terms of artificial nests, and building artificial nests for them was among the earliest management strategies designed to help them recover from population declines (Henny, 1977b). Techniques to provide artificial nests include killing live trees to create snags attractive to Ospreys (Glinski et al., 1983) and topping live trees; Airola and Shubert (1981) cut the tops off trees with trunks more than 35 cm (14 in) in diameter and built platforms on the top (Fig. 6C). See some examples of other Osprey nest platforms in Figs. 5-8. Construction details for a variety of Osprey nest platforms to be used in trees, on existing poles or towers, and self-standing nest platforms are given in Ewins (1994). The use of such platforms has benefitted Ospreys by increasing the breeding population, decreasing nestling mortality, and increasing fledging rates (Rhodes, 1972; Postupalsky, 1978; Houston and Scott, 1992).

Ewins (1994) made the following recommendations regarding placement of Osprey nest platforms:

  1. Place them within 50 m (165 ft) of water preferably 1-2 m (3-6 ft) deep.
  2. Use small rock islets, if possible, for predator protection.
  3. Put structures in the highest trees available or on poles more than10 m (30 m) from the nearest trees because Ospreys need room to maneuver in flight.
  4. Place structures at least 100 m(330 ft) from houses or heavily traveled roads.
  5. If platforms are on poles on dry ground, use an anti-predator guard on the pole.
  6. Space platforms at least 200 m (660 ft) apart.
  7. Avoid areas with lots of Bald Eagles (Haliaeetus leucocephalus).
  8. Contact the local wildlife agency before erecting platforms to make sure that Ospreys will not interfere with sensitive wildlife.

Construction notes from Ewings (1994) include:

  1. Cedar is the best wood to use. Avoid pressure treated wood because it can leach preservatives into water courses.
  2. Use galvanized nails, bolts, and wire. Pre-drill holes to avoid splitting wood.
  3. If no tree perches are located near the platform, nail a length of wood to the platform sticking out 1 m (3 ft) for a perch.
  4. If raccoons (Procyon lotor) are in the vicinity, it is essential to firmly wrap and nail a 1.5-2 m (5-6 ft) length of sheet metal (aluminum, steel, or tin) around the pole to prevent raccoons from climbing to the platform.

Osprey nest platform designs

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osprey nest platform

Quadrapod Osprey nest platform. Designed for stability in water that freezes(modified from Ewins, 1994).

osprey nesting platform

U.S. Bureau of Reclamation design Osprey nest platform (modified from Ewins, 1994)

osprey nest structures

A. Georgian Bay design for mounting on bedrock. B. Ontario Ministry of Natural Resources and Environment Canada design made from hardwood industrial pallet (modified from Ewins, 1994).

osprey nesting structures

A. International Osprey Foundation design. B. Minnesota design. C. Platform for top of sawn-off tree (modified from Ewins, 1994).