When will egg-laying begin?

So when will Mom Decorah, Mom North, and Mom FSV begin laying eggs? We don’t have a timetable, but past years can help determine what to expect at each nest. February may be about flowers and chocolate for some of you, but it is all about eggs for us!

Decorah Eagles
For the past two years, Mom has laid her first egg on February 18. Her earliest laying date occurred on February 17, 2012: an uncommonly mild winter. Her latest first-egg laying date occurred on March 2, 2009: her first year with Dad. We’ll be looking for egg-laying to start sometime between the 18th and the 21st this year, although Mom could surprise us! Given her stable laying history and the relatively mild winter, I’m looking for eggs on the early side this year…but I’ve been wrong before.

Fort St. Vrain Eagles
Mom FSV usually lays her first egg just a tad earlier than Mom Decorah. Her earliest laying dates occurred on February 14 in 2010 and 2015. Her latest first-egg date occurred on March 3rd, 2007. Assuming that Mom FSV has been here since 2007, I’m looking for egg-laying to start between February 14 and February 16.

Why am I assuming that Mom FSV has been here since 2007? A look at Fort St. Vrain’s nesting chronology shows us that egg-laying started on February 17 in 2006. It moved forward to March 3rd in 2007, retreated to February 27 in 2008, and retreated again to February 17 in 2009. We’ve seen the arrival of new female peregrines significantly change nesting chronology, often (but not always) shifting the first egg-laying date later – a trend that will often drift earlier again if she remains on site in subsequent years. It appears that the same thing might be true for female eagles.

Decorah North Eagles
Last year, several people speculated that Mom North was a first-year Mom. They cited what seemed like inexperience on Mom North’s part, especially when comparing her to Mom Decorah. She also laid her first egg on March 11 – significantly later than Mom Decorah. Will first-egg timing move earlier this year? If it does, those speculations might be correct!

  • In scenario one (Mom North has been here for several years), egg-laying will begin around March 11.
  • In scenario two (Mom North was new to egg-laying last year), egg-laying will probably move a little earlier. We don’t have a lot of comparisons to guide us, but I would look for first egg timing to move earlier by five days or more if scenario two is the case.

In the meantime, all three nests are giving us plenty to watch as the eagles haul in sticks and soft nesting materials, begin working on the area underlying the likely nest cup, and move deeper into courtship. The recent spate of warm weather in Decorah has also brought out visitors, including male and female red-headed woodpeckers, an intrepid squirrel, and a Cooper’s hawk! We will round them up on Facebook later today.