Great Blue Herons build their nests in a variety of places.  They can be on the ground, on cliffs, among bulrushes or in fairly large trees.

The male provides fish for the female who incubates the eggs full-time for between 32 and 48 days.  (The incubation time varies a lot depending on which continent the birds live on). 

Platform nests are typically very large and get bigger every year as new material is added to freshen up the nest for the new breeding season.  They can be build on the ground, on high ledges, in trees, on telephone poles or on man-made platforms provided for some species subject to concern.
  

Ospreys usually nest in trees or on  man-made platforms not far from water.  Nests are often reused for many years and get to be very large.  A variety of different materials are used to make or re-surface the nests which are large enough to accommodate usually 3 growing birds and fairly large fish (up to four pounds or so) which are provided for them to eat.

Usually around 52 days after hatching, the young are able to fly though they remain near the nest where they feed on fish provided by the parents.

They lay from 3 to 7 eggs but usually 4, which both parents incubate for about 28 days tuning the eggs by rolling them with their bills about every two hours.  Some of the young can fly after about 60 days but usually stay around the nest from 64 to 81 days after hatching.

http://allaboutnest.blogspot.com

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