Better late than never, here’s the graphic of nesting success for the spring season. The Wood Duck number is a minimum. We had two nests for which we never took a good count of eggs, and a third nest that perhaps was predated. I did not count these nests in the year’s total.
The Hooded Mergansers were 40 for 51 (78%) and the Wood Ducks were 32 for 86 (37%). First estimated hatch date for the hoodies was 4 April, and the last estimated hatch date for the woodies was 29 June.
I happened to be checking a report and discovered that I had recently passed an important (to me) milestone with Learning Ally (formerly Recording for the Blind & Dyslexic, formerly Recording for the Blind): 2,000 volunteer hours, the equivalent of one year of 40 hours/week service. It took me almost 24 years to get there, and I’m pretty chuffed about it.
I started with open reel analog recording, made the transition to digital, and moved into virtual studio recording. And the new editions of textbooks keep coming.
On to 2,500 hours!
My final report for the ducks and mergs team this season:
Well, our box score for the season shows a lot of at-bats but not too many runs across the plate. The mergansers started 10 clutches but only hatched 4; the Wood Ducks started 5 but only completed 1. We had evidence of predation in only 1 box (raccoon, #60). A possible hypothesis to explain the high rate of nest abandonment by the mergansers is simply that there were too many birds chasing scarce resources.
The egg and hatchling counts are similarly depressed: 139 eggs laid by the Hooded Mergansers, with 52 hatched (37%); 34 eggs laid by the Wood Ducks, with 7 hatched (21%). Summary worksheet from our monitoring.
A recap of the boxes: I applied some insulating foam to patch gaps in boxes #1 and #3. Boxes #4 and #7 should be replaced. A map of nest box locations.
Tiny little box #5 was put to good use this year! It was the site of our single successful Wood Duck nest. During (10 June) at left and after (24 June) at right.
Monitors, thank you for all your help!
From my summary report to the team:
As for predation by the snakes, I wouldn’t move any of the boxes just on the evidence of this season. Last year it was boxes #1 and #3 where we had a problem; this year it was #7 and #62.
Local conditions around box #69 have changed. Past years, it was overrun with Typha sp. by mid-May. This year, it remained clear of veg.
As for nest structures for Mallard and American Black Duck, let us know where you’ve placed them and we will try to work them into our monitoring routine. My references show that the nesting season for these birds extends later into the summer, so we would have the opportunity to extend our work season.
A pattern that I’ve noticed over the years is that the fledge-to-eggs ratio for Hooded Merganser is usually higher than that for Wood Duck. A couple of hypotheses:
(1) Since the mergs start laying eggs a little earlier than the woodies, perhaps they out-compete them and occupy the more favorable boxes for that year. (We don’t see that one species is particularly faithful to a box, and indeed since we see a few mixed clutches, a box may be considered favorable by both species.)
(2) We are more likely to see “dump” and “drop” nests for the woodies: boxes with 20+ eggs. And with these jumbo clutch sizes, it’s more difficult to incubate all the eggs sufficiently.
We bounced back from the dismal 2015.
From my final report to the team:
It seems like every year I get this final report put together later and later. At any rate, this was a much more successful nesting year for our Wood Ducks and Hooded Mergansers.
Of our 16 boxes that we monitored, we had 16 nests started. That is, one box had a double brood and only one box this year was not used. Of the 16 nests, 13 were (predominantly) Wood Duck, and three Hooded Merganser. (We often have some eggs from the other species in the nest, which messes up the recordkeeping that I submit to the Cornell Lab.) And of the 16, 13 fledged at least some young, one failed, and two I’m just not sure about. The two questionable boxes are #1 and #3, near the tower. When we checked on 8 May, the evidence indicated predation, but when we visited on 22 May, I saw evidence of membranes, indicating that some eggs had hatched.
So, not counting the two questionable boxes, we have a fledge-to-eggs rate of 70% (114/163) for the Woodies and 91% (31/34) for the Hoodies….
Thanks again, everyone, for the hard work, and we’ll see you in February/March! When it should be colder.
Not a great-looking set of data for 2015. We’ll get ’em next year.
Today’s not his birthday, but hats off anyway to Frederick Vernon Coville, commercializer of blueberries.
We wrapped up the nesting season two weekends ago. The Wood Ducks bounced back after a couple of slower years. I’ve noticed a pattern recently: not only do the Hooded Mergansers get started earlier, but overall they tend to fledge a greater percentage of the eggs they lay—85% or better, seven of the last nine years. The Wood Ducks, on the other hand, are subject to dump/drop nests that don’t fledge anything. (One such nest a year is typical for us, out of 15 to 20 boxes being monitored.) In six of the same past nine years, our fledging rate for woodies has been 67% or lower.
The sanity-checker script at NestWatch is skeptical that we have mergs laying 14 eggs in a clutch, and laying as early as the last days of February. I invite the Lab scientists to come check the boxes for themselves.
I took a new camera with me to the park: it’s still a happy snap, but the optical zoom is better suited for quick shots of butterflies. The spangles on the underside of the hindwing of a Speyeria cybele are not usually the first thing you see, but they are diagnostic for ID.
Paul and I checked all the boxes last week and counted eggs for the remaining three nests. Swamp Rose (Rosa palustris) was in bloom, attended by various pollinators and other hangers-on.
The Hooded Mergansers continue to be more successful in our 16 boxes. We saw 7 clutches that were primarily merg, yielding 103 eggs, hatching 92. The Wood Ducks produced 6 clutches, laying 72 eggs but only hatching 48. Of the 13 total clutches, there were eggs of the other species in 4 of them. Our combined species total of 140 ducklings is the maximum over the 30-odd years that we have data for.
The two boxes that were relocated in preparation for the construction project (#77 and #6) were both successful. Box #13 had eggs
laid in it over a period of about 6 weeks, from 1 March to 13 April. In the end, 11 of the 14 eggs hatched.
A new season of nature blogging, and I’m thinking I should jazz up the brand a little bit, maybe add a little more sizzle. Something like this:
Generated by the PULP-O-MIZER ↬ The Endeavour
I finally got my recordkeeping caught up for the Wood Duck/Hooded Merganser nesting season. Heck, most of these birds are probably on their way to Florida and points south by now.
The birds made good use of the boxes this year, especially the two new ones that we installed in February. In 16 boxes, we had 12 nesting attempts, all of them successful. No dump nests: our largest clutch was a combined Wood Duck/Hooded Merganser nest with 18 eggs, of which 16 hatched.
The mergs continue to produce more than the woodies for the third year running. 70 HM eggs laid, 63 hatched; 57 WD eggs laid, 46 hatched. The count for the woodies is probably a little low, as we had one box where we never did get a complete egg count. The Wood Ducks made as many nests as the Hooded Mergansers (5 each, with 2 mixed), but their clutches were, on the average, smaller.
To illustrate my point about Deon’s word choices, here’s a word cloud of his entire text, common words omitted and one possessive collapsed.
Join the (first?) area Cricket Crawl on 24 August, a census of late summer crickets and katydids.