I would consult one of the organisations, which deal with protected bird species, as there might be some strict guidelines in place.
They normaly migrate to africa
A large mass of sticks, similar to a bald eagle's nest.
Usually in the first 2 weeks of March
Osprey build a fairly large nest of sticks in the top of a dead tree or on a man-made nesting platform.Usually they will pick a very high place near a body of water, and use sticks and branches and long grasses to build it out of.
they sleep in big bushy nest made of leaves, branches, mud and twigs
Our ospreys have built their nest mainly of twigs and branches of all types and sizes. There is also plant and grass material as well as dried seaweed. Some other types of materials are string, rope, polypropylene rope well as plastic material such as supermarket bags. The nest has a lot of depth to it to provide heat retention and as a safety factor for keeping the chick in the nest since nests are mostly built near water or on platforms in the water. Our ospreys had elected to build their nest on the last "dolphin" (a group of three pilings used to secure a dock), of our dock. We had long nails hammered into the tops to keep seagulls off of them. These nails provided a base in which the ospreys were able to lay and weave the foundation for the nest. It took three seasons for our ospreys to build the nest large enough and secure enough to successfully nest and hatch their eggs. The first eggs hatched June12th, 2011. The male is fishing for bunker which he brings to the nest. The female then takes over and feeds herself and her chick from his catch. They are very skittish when nesting, so we elected not to use our boat until after the young ospreys have fledged.
The crows nest.
I think a pair are building a nest on my front lawn.
Crow's nest
mutualism ............ No, its commensalism
behavioral
Yes, building a nest is a learned behavior for robins. While they have innate instincts related to nest-building, they also learn the specific skills and techniques from observing other robins or through trial and error.