This tower site has been used for at least two years. Today we observed one osprey making multiple trips to what remains of last year's nest with restoration branches.
What to look for
Look for 2 adults on the nest. The adult pair will show pair bonding behaviors such as vocalizations, aerial sky dances, and the male feeding the female fish. You may see the pair copulating, which typically begins 14 days before laying eggs.
Females will lay 1 - 4 eggs at a rate of one egg every 1 - 2 days. After laying, incubation starts. Look for adults taking turns sitting low in the nest incubating eggs. The incubation period can last 35 - 43 days.
Chicks hatch ~39 days after incubation begins. Look for adults bringing food to the nest and making "head bows" into the center. Chicks typically can't be seen until they are 2 - 3 weeks old, so feeding behavior is the only way to know chicks are there.
Around 4 weeks after hatching, look for the heads of chicks to show over the rim of the nest, particularly when adults bring food to the nest. Other times they lie flat and are harder to see. Count the number of chicks in the nest before they learn to fly
Chicks begin flying around 7 - 8 weeks old, and are still fed by the adults. Count the number of chicks who have successfully fledged the nest and are observed flying.
Chick Last Observed
4 - 10 weeks after fledging, chicks begin leaving the nest area to migrate south, once they have learned to fly and feed themselves. Record the date that the last chick left the nest.
Look for signs of nest failure like adult abandonment, adults no longer incubating eggs or feeding young.
It has been a little over a month since the adults at the nest have started acting like the clutch had hatched - constant incubation had ceased, and adults appeared to be feeding something low in the nest...but there was no other way to verify existence or number of chicks. Today, finally!, we saw at least one.
July 4, 2012. Independence Day takes on a different meaning! Stopped by to see if the frustrated chick in the nest was making any progress with flight. Saw one of the adults perched on the bars around the nest, but no chick in or around the nest. Went into worry mode - this nest's location on a cell tower between two busy roads leaves very little room for flight practice error. A few minutes later we saw another osprey sail in and land comfortably on the rails - took a look through the scope and we were thrilled to see that this new arrival was the chick/fledgling returning to the nest!
July 1, 2012 Stopped by to check on this nest, found one VERY frustrated chick flapping and vocalizing and not achieving lift-off. The only component left to master is The Hop, and this bird will be in the air!