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.
Clearly some activity in the nest, Mom either in or standing just outside, Dad standing guard at times as well. When Mom is outside the nest, movement can be seen in the nest but still difficult to tell how many chicks there may be.
Date of arrival is estimated. First observed on March 17th and they had already started to rebuild the nest that had been removed over the summer for tower equipment maintenance. Rebuilding has not gotten very far yet. There were 3 birds active in the area in the morning. Two were perching on the tower in the evening.
Now can see 3 chicks, one is noticeably larger and more active than the others and possibly soon to fledge. Has been observed standing on the edge of the nest eating with adult and standing on one of the tower posts.
5 pm, female sitting on the tower just outside the nest, the male was inside the nest.
5:20 pm, the male leaves the nest, the female takes his place in the nest
5:45 she turns the eggs
6:20 pm Male returns with a fish and drops it in the nest, leaves again
7 pm, He returns with another fish
Female was low in the nest most of the time of observation (1.5 hours) and did appear to turn the eggs once. Male was flying in the vicinity and at one point returned with a very large fish, but perched on a nearby pine tree to eat it. Female called to him during this time and even flew out very briefly and then back to the nest.