Duckling survival rate? Do duck hens share parenting duty?

[Jasam]

So roughly how many ducklings make it to adulthood from an average brood? Is it common for females to combine their efforts at guarding the ducklings, or even babysit so the other can gather food?

Some background and observations that led to the question:

I'm in a subdivision outside Houston that has a dozen horseshoe lakes interspersed throughout the neighborhoods, remnants of the bayou floodplain before the levees were built. The one I overlook has about 1.5 miles of shoreline, varies from 150-500' in width, is enclosed but aerated with fountains, and the edges are lined with stone or concrete curb. My side has a long narrow artificial island, 30' wide and 600' long, with about 100' of water on either side, with about 20 deciduous trees (mostly water cypress), grass and clover. Both it and the grass shoreline are occasionally mowed or weed-whacked by landscapers (egg-thieves!)

We have a large collection of Muscovy, Mallard, and Whistling Ducks, along with a single tag-along misfit Baby Huey, a white domestic or Pekin presumably dumped after the novelty of an Easter gift wore off. Actually 4 of his kin sometimes swim by, but for some reason he never associates with them and keeps trying to be a Mallard. Plenty of American Coots and also a dozen+ geese. I guess these are snow geese because most are pure white, though they don't have any black on the wings. Some have plenty of gray mixed in on their back, perhaps still in a younger stage?

Those are the residents, attracted by a neighbor who once or twice daily tosses out a pot of seeds, grains, breads, crackers, or popcorn. Not sure if there is any fish in the lake, but an Anhinga or two can be seen most days. A few days ago several Black-Crowned Night Herons began prowling about. More on that in a second.

About 3 weeks ago I saw a Muscovy lead her ducklings down to the pond's edge while she got a drink, but they didn't go in. That was the only sighting of young until yesterday (I work from home so keep an eye on the pond pretty much every day.) At lunch yesterday I noticed a lone Muscovy on the north end of the island leading ducklings through the tall clover. They took a half-hour swim and then climbed back up the island's curb, which was a bit amazing given that it extended up about 3 times their height. It was easy to count them as they climbed almost one by one, and there were 13 total.

This had attracted several Night Herons, and over a few hours they maneuvered and waited, in between trying to chase off each other. The Muscovy was cautious at first, but after a bit would start walking again, occasionally half rising and flapping her wings when a heron got too close. But sure enough, eventually one swooped in and picked up a duckling, twice in 10 minutes. The dance continued off and on, but by sundown she still had 11 ducklings remaining.

This morning the lone Muscovy was again at the north end of the island (she never has seemed to venture beyond the north half of the island and the waters or immediate shoreline around it.) But it was a bit shocking when she went for a swim that only a single duckling was with her. The 4 herons were still present, and about a half hour later one swooped in and took away the last duckling. The hen then did the dunking of the neck under water and splashing that they often do after mating, and then went back to wandering and sitting at the north end of the island, by herself.

So how many ducklings is it common for a hen to lose in a season? I was a bit surprised to see the hen wander with the ducklings when predator birds were on either side of her, within 20-40 feet or so. She appeared constantly aware of them, but was that riskier than normal behavior for a Muscovy hen? I.e., was this perhaps a hen with poor parenting instincts compared to most?

But several hours later there was a twist. I looked out at the island and the solo hen was nowhere on it, however a Muscovy had 20 ducklings following it on a swim around the north end of the tiny island. There was another hen swimming just a bit behind but pretty much with them. After a while they all pulled up to the north side of the tiny island, but then then one led 6 ducklings up and onto the island while the other hen took the remaining 14 for another half hour of swimming. The Muscovy with the 6 ducklings on the island had the docile nature of yesterday's hen as they wandered through the clover, with herons again watching. The hen with the 14 however has all the markings of the one from yesterday, so I'm not sure which is which. The hen with the 14 was more aggressive with the ducklings in the water, often pecking at individuals. Yet I was surprised how far she'd let them float away at times, sometimes 3 or more feet away on each side. At one point a heron made a couple of attempts at grabbing a duckling, but the hen scared it off just in the nick of time. In fact it seems that if the herons were more assertive and less skittish, they could pick off the majority of ducklings one by one. I don't see how a hen with a large flock could fight off determined predator birds.

So after an hour or so of separation, the hen with 6 on the island led them back in the water, where they soon joined the hen with 14. They swam off to the opposite shore again as a group of 2 hens and 20 ducklings, prompting my post. Is it unusual for duck hens to work together in leading their ducklings around? Do they sometimes take turns looking after the group so the other hen can wander off? Is it possible that this morning one hen was looking after a combined flock and the other hen swam off with a single straggler duckling following her (the one the heron soon ate?)

Thanks for any replies.

 

[dorsetduckowner]

Hi, what a lovely and interesting story! A bit like a ducky soap opera! I am in the Uk so we dont really get muscovy living wild so I am not sure if they creche their young. I do have lots f experience with mallard babies though and sometimes the babies may get mixed up with other broods, but the mums don't usually take to the interloper babies and peck at them until they go back to their own mum.
Predatory birds can take a whole flock of 14 over a few days and if you have hungry herons, they could take the whole brood in a day.
Here I would expect 1-3 babies to make it to adulthood out of a brood of 12-14 unless they are fed and protected from predators. Very sad.
Keep us posted!

 

[abitquackers]

That's fascinating about the idea of a creche. I don't know regarding hens and sharing broods, but when I was 12 we use to live by a mill pond. It had some mallards and a pair of swans. One year we found all ducklings bar two gradually killed over a few days. There were two cygnets on the lake at the time and we witnessed swans killing the ducklings. The adult ducks left and did not return for a couple of days. We ended up rescuing the ducklings who were left and they were carefully relocated and reintroduced to the wild. In that case, none of the ducklings would have made it from any of the broods on the pond, so I'm not surprised to hear about the herons being able to take the whole brood in a day.

 

[Marigold]

I enjoyed this story very much.I suppose that to replace the parent birds a duck would need to have a survival rate of 1-3 ducklings on average. Like many species ducklings exist partly to act as food for predators higher up the food chain so consequently a high predation/death rate is normal. Species here such as bluetits have broods of 12+ most of which end up as food for someone else. Otherwise the area would-be overrun with bluetits - or ducklings. Your account of the parent birds working together to protect their young is very interesting. Perhaps this indicates natural selection in action if this strategy is not very common as the surviving ducklings might be better able to protect their own broods as adults by cooperation with another mother duck?