Sure seems to be. An eagle-eyed YouTube viewer pointed out an egg-shaped object precariously perched on the steep side of the nest, partially obscured by foliage. Our Loon Cam technical wizard reviewed the archives and it appears that the egg has been doing some short-distance traveling since it was accidently kicked out of the nest during the hectic nest building on May 28 (see the 5/29 blob post “Rain, Rain, Go Away!” below).
A common theme in frequently asked questions concerns the viability of a fertilized loon egg. How cold can a loon egg get and still maintain viability? How hot? Does an unincubated egg remain in suspended animation and, if so, for how long? The truth is that we don’t have precise answers for these questions. And much of what we do know is based on other species of birds. When you are dealing with a state-threatened species, you can’t afford to experiment with the eggs. But based on what we think we know, let’s take a stab at some of the questions.
What goes on with the first laid egg during sporadic incubation before the second egg is laid? Since the egg isn’t being kept warm, we can assume that the embryo is not developing at the rate it normally would. But if we look at the evolution of eggs we see that more primitive eggs (amphibians and reptiles) are never actively incubated. Hatch time is governed by temperature. It seems logical that a freshly laid and unincubated loon egg could experience some development; just not as much as if it were being incubated. However, that would still give the first egg a developmental advantage over the second egg.
But what if the first egg isn’t incubated at all for 60 hours? Good question! I’ve been told that some fertilized bird eggs can be refrigerated for a week and remain viable. What we know for sure is that an unincubated loon egg will never hatch, but how long an egg can remain unincubated and still be viable is up for grabs. In the case of Loon Cam 1, the first egg got next to no incubation for the first 60 hours. If the nest hadn’t lost an egg and both eggs hatched, then we would know that the limit for viability is at least 60 hours. But, alas, an egg was lost so we won’t get the opportunity to increase our knowledge on this nest.
Can an egg get too hot? Yes. Eggs are protein-rich. Proteins are very susceptible to heat, which will cause them to change shape and no longer function properly. That’s why egg whites quickly solidify when fried. It’s estimated that, on a very hot day in full sun, the proteins in an exposed egg could be damaged in as little as a half hour. You’ll see overheated loons take a break from the nest during the hottest summer days, but you’ll rarely see them off the nest for more than 15 minutes.
We Have an Egg!
The first egg was laid at approximately 8:21 am today. If all goes well, we’ll have a second egg tomorrow. The loons will usually have very sporadic incubation until the second egg is laid. After that, incubation will be almost non-stop, with occasional breaks of less than 15 minutes for cooling off on hot days and shift changes. Yes, male and female share the nest sitting chore.
Other causes of leaving the nest during incubation include intruding loons (and humans), chasing egg predators and black flies if they are numerous enough. So far, the black flies are present but not very thick.
They’re Getting Serious
Is the female ready to lay the first egg? The pair kicked in to high gear this morning and spent a good two hours of non-stop nest building, as well as some work in the rain last evening. Prior to this, their attempts were sparse and halfhearted. In fact, it seemed that they were spending more time window shopping for other possible nest sites. But now it seems they are sticking with last year’s nest site.
Nest Building and Nest Site Selection
Our loon pair continues to build up the nest mound, although at a leisurely rate. In fact, it seems they spend more time inspecting other nearby spots as possible new nest sites. We shouldn’t be surprised at this. This pair has used different sites in the past. In fact, the current nest is the second location they’ve used since we began the loon cam in 2015. Also, loons are much more likely to abandon a nest location after a failed nesting attempt. Although by LPC standards last year’s nesting attempt was successful (they hatched a chick), the chick was taken off the nest by an eagle just hours after hatching. So it shouldn’t be surprising if the loons are contemplating a change in location, especially considering that the eagle has blatantly made its presence known to the pair.
The good news (for camera logistics) and bad news (for the loons) is, other than this general location, there is no desirable nesting habitat on this lake. There are no islands nor sizable marshes. The mucky peat mounds in this cove offer the best nesting opportunities for the loons. Chances are excellent that if the nest is moved it will still be within sight of the camera. But predicting loon behavior can be a fool’s errand. We’ll just have to keep watching.