I’ve compiled and analyzed data from wild Bald Eagle nest cams from 2006-2016 concerning how long it takes for an egg to hatch.

In some ways the numbers support what veteran cam watchers have come to know about parents’ incubation behavior, delayed hatching of the first egg, and how close together hatches can occur in comparison to the minimum 3 days between egg-layings.

For instance, the first egg almost always takes longer to hatch than later eggs. Observations from these nests give us a pretty good idea of how much longer.

And hatches can occur as few as 4 hours apart. But for which eggs in a clutch?  The data tell us.

The data also show some more subtle facts, such as differences in hatch timings between a 2-egg clutch and a 3-egg clutch.

There are some unexpected numbers, such as the average time overall between when an egg is laid and when it hatches.  It’s 36.5 days.  Not 34 or 35.

In fact, the shortest hatch time on record at these wild Bald Eagle nests was 34 days 11 hours 1 minute after the egg was laid.  And that fast time is an outlier in the data.

The longest time on record was 40 days 12 hours 17 minutes.

And whether a nest is in a northern climate or a southern climate seems to make no difference in whether hatching is delayed.

Go here to take a deep dive into the data and my analyses.