It’s been an “interesting” three days since we first saw the pip on what we assume was egg #1. The chick hatched in the dark, early hours of Thursday morning but we didn’t get a look at it until daylight. The loons continued incubating the second egg and we hoped to see another hatch soon. The following night, loon cam watchers reported hearing peeps and tapping coming from the egg (it’s so great to have a microphone on the raft!) and our expectations were high.
Meanwhile, the hatched chick was getting rambunctious and the parents had their hands (wings?) full, trying to incubate an egg while taking care of a precocious chick. By the time daylight arrived on Friday, both parents were spending more time with the chick than incubating the egg. Viewers reported and discussed interesting features on the surface of the egg but we never saw a classic pip (the beginnings of a chick emerging from the shell. By nightfall, it was apparent that the loons were more concerned with the chick and ignoring the egg.
Today it’s safe to say that the second egg will not hatch and possibly never would have hatched. The loons haven’t been back to the nest and they are busy feeding and guarding the chick. Soon they will start moving toward the brooding area, which is in another cove. The loon cam was shut down shortly after noon.
Losing an egg is a disappointment but the loons have to protect their investment, which is now a healthy chick in the water. When we look at the big picture, our two Loon Cam pairs have hatched three healthy chicks this year. If they all survive to the end of the season, then that is a roaring success; three times the statewide average. Here’s wishing a long life to the chicks and their parents, who we hope to see back here next year, contributing again to a sustainable loon population.
Sure looks like it!
Comments in the YouTube chat show some misconceptions about loon anatomy, particularly about anatomical structures lacking in loons. Here are some features found in a wide range of birds but not found in loons:
The Crop – A crop is an enlargement of the esophagus that allows storage of food prior to continuing to the stomach (more properly known as gizzard or ventriculus). It allows birds to gorge on food where it is plentiful and then digest the food when they’ve moved to a safer location. It also does some predigestion preparation and may be useful in combating harmful bacteria. Omnivorous and herbivorous birds are most likely to have a crop, and to have a well developed, complex, lobed crop. Loons are nearly exclusive fish eaters (piscivores) and that may have something to do with why they don’t have crops. Penguins are another piscivorous bird without a crop. Cormorants have a rudimentary crop, which is nothing more than an extra wide section in the esophagus.
Brood Patch – A brood patch is a featherless area on the underside of an incubating bird. It usually has a number of blood vessels near the skin and it aids in heat transfer to the egg. Brood patches typically are only present during breeding season. Loons seem to manage well without a brood patch. Exactly why loons don’t have a brood patch is unknown but it might have something to do with waterproofing. A loon’s feathers form a watertight envelope and they can control buoyancy by expanding and contracting their feathers. Perhaps a brood patch could compromise the watertight seal.
Egg Tooth – An egg tooth is a protuberance used by the offspring of egg-laying animals to break through the eggshell. On birds, it is normally found on the top of the upper mandible and falls off within a few days after hatching. Loon chicks can do well without an egg tooth. Their bill is well formed at hatch time, and although it isn’t as sharp and dagger-like as an adults, it’s still more than adequate for punching a hole in the eggshell. Loon chicks are precocial, meaning that they are fully developed and ready to jump in the water and swim with their parents the same day that they hatch. They are well past the stage where they would need an egg tooth.
Now that the loon cam season is complete, we can review the events we witnessed over the past two months and see how they fit with the conventional wisdom of loon behavior and ecology. We think we know so much but we are constantly reminded that there is always more to learn. Here’s a few things that added to or reinforced our knowledge base.
Nesting loons have more ways of losing eggs than we thought. Disappearing eggs are nothing new. It’s more common than you might think. Loons can accidentally knock an egg out of the nest. Boat wakes can wash an egg out of the nest. Some predators can carry eggs away from the nest (raccoons and eagles are good examples). We’ve even had some suspected human thievery. But a loon accidentally burying an egg wasn’t on our radar until the Nest Cam #1 loons demonstrated that it could happen. Had we known that there were two eggs on the nest but didn’t have the camera to witness the occurrence, we would have listed the ultimate fate of the egg as unknown, or possibly unknown predation if a biologist had a chance to survey the area shortly after the egg disappeared.
An egg in the middle of the incubation phase can remain unattended for 10 hours and still remain viable. The Loon Cam #2 loons demonstrated this. This is just one data point and certainly doesn’t mean that all eggs would remain viable. Had the day been sunnier and warmer, or much cooler, the outcome may have been different. But each new observation narrows the unknown range.
Predation by eagles is increasing in NH. This isn’t really new, nor is it unexpected. In fact, LPC Senior Biologist John Cooley recent published a paper concerning this in the Wilson Journal of Ornithology. But watching it happen live on Loon Cam #1 certainly left an indelible impression on the minds of the viewers. And it demonstrates that even the smallest loon pond can be subject to predation by an expanding eagle population.
Loons have a wide variety of nest sitting schedules. The literature says that female loons are more likely to do the nighttime incubation and they tend to invest more time to incubation as the hatch date approaches. Observation of the Loon Cams over the past few years show that this is not always the case. The male on Loon Cam #1 does a lot of the nighttime sitting and he is consistently on the nest during hatch, whereas the female has been known to take off for extended periods when hatching is imminent. All pairs we have observed seem to have a very fluid schedule. As soon as we start predicting who will be on the nest at a certain time, the pair will call our bluff.
It all adds to our knowledge base and reminds us that we don’t know everything and sometimes we don’t even know what we think we know. Here’s looking forward to next year’s humbling lessons from the Loon Cam loons.