At around 6 am this morning, Dad finished up his nest sitting. When he got off the nest, it was evident that one of the eggs was crushed. Mom climbed on the nest nine minutes later and noticed the broken egg. She picked up the largest piece, removed it from the raft and did not get back on the nest. Four+ hours later and the remaining egg still has not been incubated.
So, how did the egg get crushed? Possibly the sitting loon got startled during the intense thunderstorm we had last night. But some avid loon cam watchers say the egg looked “odd” yesterday. A close review of the archived video may help pin down the time and cause.
So what happens now? We aren’t sure of the condition of the remaining egg. It looks like it may also be damaged but it seems that the very few times our cam operator isn’t available – Bill puts an incredible amount of hours into this project – is when weird things happen. A zoom-in might answer the question. If the remaining egg is also broken, then we have a nest failure. The loons could possibly re-nest but they would have to act quickly. It would have to be by early-mid-July at the latest.
If the remaining egg is still intact, then it’s a question of whether or not the loons will resume incubation soon. This could go either way. It all depends on the cause of the broken egg and the individual loons. Often they will continue to incubate the surviving egg but sometimes they abandon the nest. Time will tell. And as I check the loon cam just now (10:48 am), Dad is climbing on the nest and getting himself comfy. Check that… Dad left the nest. We’ll just have to wait this out and see what happens in the long term.
We knew it could be true. It was just hard to accept. Eggs being accidentally buried in the nest wasn’t on our radar; it’s not something that had come up before. Still, we were fairly certain that the egg was either knocked out of the nest or buried during a frantic nest building session on May 28, when the loons were battling a continuously rising water level.
Our post-hatch nest inspection was more thorough than usual. In addition to getting GPS coordinates, collecting eggshell fragments and inspecting the general area for anything unusual, we dismantled the nest (not something we want to do on a regular basis) and… Voila!
https://www.youtube.com/watch?v=i5UQzB-c_zE
And we have a great, explicit clip of the first egg being layed at 7:30 this evening.
https://www.youtube.com/watch?v=xuxqz8ANB90
So, When Will the Eggs Hatch?
It’s been twenty-three days of incubation now and getting close to hatch time. Reports of the average time for incubation generally call for 27 to 28 days. However, reported ranges of incubation times span from 25 to 30 days. Now that we’ve been closely following this pair for six years, it would seem reasonable that we could narrow that range down by calculating previous incubation times for this pair. The problem is that because of nest failures and egg losses or abandonments we only have two definite times for the first laid egg and two less definite times for the second laid egg.
For the first laid egg, we have 27 days, 3 hours (2017) and approximately 26 days, 10 hours (2018; approximate because we don’t know exactly when it was laid overnight). So the average is a little shy of a full 27 days. This year’s first egg was laid at 8:21 am on May 18th. A full 27 days would be the morning of Sunday, June 14th. It’s also interesting to note that, for this pair, all four recorded hatch times occurred between midnight and 6:00 am. So sometime in the early morning of Sunday looks promising.
We can do the same for the second egg. The records are a little sketchy but it appears that a reasonable estimate for incubation time is 26-1/2 days. It would seem the earliest we could expect a hatch would be Monday night or Tuesday morning.
Now all that’s left is waiting to see if the loons show consistency or decide to make a fool of me. Having come to know these two, I’m thinking the smart money is on the latter.
Nest Visitors
Regular loon cam watchers have witnessed various visitors to the nest, including painted turtles, snapping turtles, great blue herons, muskrats and eagles. Most of these visitors present little threat to nesting loons. In fact, loons can be quite tolerant of painted turtles, herons and muskrats, all of which are likely to use loon nest hummocks and the floating nesting rafts for perching (herons), sun basking (painted turtles) or feeding stations (muskrats). Snapping turtles can be a threat to chicks after they leave the nest but they are not a significant egg predator. Adult loons can easily defend a nest from a snapping turtle. Eagles, on the other hand, have been known to attack chicks, and adult loons in some cases, while on the nest. Most of our recorded eagle attacks in New Hampshire have occurred against chicks in the water after leaving the nest.
The leading cause of egg predation in New Hampshire is mammalian predation, with raccoons doing most of it. This is presumed to be the reason why loons prefer to nest on small islands or hummocks in marshes and use the mainland shore as a last resort. The more difficult it is for a terrestrial animal to access the nest, the safer the eggs. Other mammals known to pilfer loon eggs include coyotes, foxes, and some members of the weasel family (mainly mink). As development steadily increases on New Hampshire’s lakes, raccoons in particular become more prevalent because they have acclimated to human presence and view us and our waste stream as a food source. That plus the loss of good nesting habitat due to development has resulted in a higher probability of nest failure due to egg predation.
Stalwart Dad
The male is pulling 20+ hour nest sitting shifts lately; certainly not unheard of for this pair but normally it occurs later in the nesting phase or it is attributable to oppressive conditions, such as black fly infestations or heat waves. With the exception of one short hot spell, nesting conditions this year have been quite tolerable. Perhaps it’s the female’s old age that makes her reluctant to incubate, or maybe it’s her innate disposition. Two years ago she was AWOL for two complete days while the eggs were hatching, apparently not even on the lake. We looked for her.
But the male has always shown a steadfast commitment to hatching the eggs. If he can solo babysit two newly hatched chicks for over 48 hours, he can handle a 20 hour nest sitting shift.