There’s not much to see on the cameras yet, but the hen was away just now (2:20pm) so I checked the nest. All the eggs except one have a small place of broken eggshell. This indicates hatching will occur soon, but a duckling rests for a while after making that first tiny break.
Virtually all of the liquid inside of the egg has been absorbed and is now part of the duckling. An air pocket forms between the egg membrane and the shell even before the eggshell is broken; the shell itself is somewhat permeable to air. A duckling’s first breaths occur when it breaks through the egg membrane and gets to this air pocket. A while after that the duckling slightly breaks the shell and that lets in additional air. Once it’s breathing it can make sounds. You can see the hen react to this sometimes.
I held each of the eggs to my ear and twice I could hear very soft peeping from the duckling and both hear and feel very tiny tap-tap-taps as it pecked at the shell. I tried to record that with my phone so I could put it online for you, but all I can hear in my recording are outdoor noises of songbirds and the breeze – I would need a better microphone to pick it up.
When the duckling is ready to get out of the egg, it starts pecking as it very slowly turns, instinctively using its wings and feet to pivot around inside the egg and eventually – many hours later – the egg is broken all the way around in a ring and falls into two pieces.
You can see the broken shells on several of the eggs, especially the one on the left. The darker egg at the top may be infertile: it shows no signs of hatching yet and is noticeably cooler than the others.
Close-up of the two eggs in the middle, showing some of the work accomplished so far by the ducklings inside.
This photo shows the camera that is bringing you the outdoor pictures. The camera itself is hidden behind black film so the ducks won’t be startled by seeing its “eye” and watching it turn.
When I checked at 4:00 this afternoon 3 of the eggs were pipped, that is, the shell was very slightly broken from the inside. The ducklings do this roughly 24 hours before they hatch so they should start to emerge sometime tomorrow.
Jump Day: Saturday, … or maybe Friday
If they’ve all hatched by tomorrow evening then they could be jumping from the nest on Friday. Otherwise they’ll leave on Saturday and right now I think that’s more likely. In all the years of watching, I’ve never seen them leave in the afternoon – they’ve always gone in the morning. We’ll see what they do this time!
The outdoor camera is now live along with the inside camera. For links to these cameras go to the main page at birdsgv.com
The west nest hen started incubating 10 eggs on about the 4th so they should hatch sometime around Independence Day. I think the eggs are mostly or even all hers because we didn’t notice any other ducks dumping eggs in that nest and 8 to 14 is a normal number for one hen. We do still see adult ducks in the creek and the yard but their nest-seeking activity has nearly disappeared as it always does this time of year.
(I was wearing gloves because I was doing garden work, but that and/or washing afterwards is a good thing to do.)
However a duck has been in the east nest box for a half hour on some days in the past week and has now laid two eggs there. She wasn’t there at all today but it’s possible she’ll be there tomorrow and there’s still a chance that this nest will also have another round of ducklings – or she might not finish. The next few days will provide the answer.
These hens might simply be late in getting started, but also if a wood duck loses her brood she may try again in the same spring season. Reasons she might lose them include a raccoon getting into the nest and eating all of the eggs or ducky-disasters such as the nest tree falling, a flood carrying all of the ducklings away, or heavy predation that takes all of the ducklings.
Fortunately those are rare, but wood duck duckling mortality averages nearly 50% during the first 6 weeks. That is one reason they have evolved to have such large broods.
It’s now very likely that the West nest box will have another batch of ducklings five or six weeks from now. There are now 6 eggs and a hen has been sitting in the box for several hours each morning.
Also a hen has already visited the recently vacant and beautifully redecorated (new wood chips) East nest box. She was in there for about 10 minutes this morning trying it out, sitting this way, then that way, then another way, all the while moving the furniture (the wood chips again) around. This is typical pre-inspection nesting behavior. So maybe there too? It has happened before that both nest boxes were used twice in one season.
The hen that is laying eggs in the West nest posed nicely for a photo this morning.
The six eggs this morning. It’s kind of silly to keep posting duck pictures that look like many others and egg pictures that look like dozens (because that’s how you count eggs) of others. I do it anyway.
I checked the East nest this morning while the duck was out and all of the eggs on the top layer were pipped. Thus I expect hatching will occur starting tonight or early tomorrow and that would make their jump day Saturday.
Also a surprise: there are now 3 eggs in the West nest. There were none just two days ago after two weeks of brief visits, so that led me to predict in the previous post that there would not be a round two for the West nest box. I should know better. Whenever I predict something (for a good example, see the paragraph just above and the headline of this posting) the ducks like to fool me. I should just stop doing that and instead always write “we’ll see” instead.
The last stages of hatching occur when the duckling uses its “egg tooth” to break through the egg membrane into an air pocket that forms in the egg between the membrane and the shell. At this time the egg white has been fully absorbed and the yolk is becoming internalized in the duckling, so there’s no free moisture inside. The duckling breathes in this air pocket and there is some air exchange through the shell, which is porous.
A while later the duckling adds to the air exchange by pecking at the egg shell in one spot (wherever its little beak is), which is called pipping the egg shell. That lets in more air.
Since the duckling is breathing it can make sound and I’ve heard faint peeping when holding a pipped egg. I think this stimulates the hen to be even more active than usual in turning the eggs. Hours later, about a day or so after pipping, the duckling has developed enough to use its legs to push and to very slowly rotate inside the egg as it pecks with its egg tooth. It takes many hours to break the egg all the way around and to finally emerge. The egg tooth is a sharp spur at the end of the ducklings bill. You can see it as a white spot after they hatch: