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EXCEPTIONAL RUBY-THROAT NUMBERS, EARLY RTHU BREEDING SUCCESS, AND TRUMPET CREEPER BLOOM TIMING
All text, maps, charts & photos © Hilton Pond Center Things picked up spectacularly in May with 46 new ruby-throats banded at the Center followed by 14 more the first half of June--meaning we were now on our second-fastest pace for banding hummers in 40 years! (The "spaghetti graph" above shows 40 years of banding rates, March through mid-June at Hilton Pond. The average rate of banding is the white dots, compared to the beige dots for the current year. The record pace--marked by a yellow line--of 60 bandings by 15 June was set in 2015, which ended up yielding our sixth-best annual total. We expect banding numbers in 2023 will follow the usual trend of substantially increasing the first week in July.) Amazingly, through 15 June 2023 we'd also re-netted or re-trapped 53 RTHU banded at the Center in 2022 or earlier--our best total by this date and far ahead of our our 40-year average of 17 returns. But in early June even more important things started to happen, as follows.
This week on 9 June we netted another streak-throated hummer (below) that resembled the old female pictured above--except its yellow gape identified it as a recent fledgling. This plus extensive dark streaking meant it almost certainly was a young male--a supposition borne out by measurements (males are smaller) and by the shape of its sixth primary feather (tapered and pointed in males, more rounded in females).
All text, maps, charts & photos © Hilton Pond Center What was especially interesting about this newest capture on the 9th was he tied for the Center's fourth-earliest-record for a fledgling RTHU; previous earlier June dates include the 4th, 5th, 6th, and 9th (three birds), with a more typical first-fledgling banding date of 1 July. This year's banding of the young hummer above--plus two more streak-throated males on 12 and 15 June--confirms local RTHU nesting success for 2023. It likewise suggests ruby-throats got a good--possibly early--start on breeding this year. With all this in mind, things look very good for local Ruby-throated Hummingbirds in 2023. Lots of new adults getting banded plus a ton of returns from previous years equals a potential for a good crop of fledglings, and maybe even double-brooding. We don't want to count the rest of Hilton Pond's hummers before they hatch, but this may be the year the Center goes broke buying sugar! All text, maps, charts & photos © Hilton Pond Center TRUMPET CREEPER--JUST IN TIME As we gazed out our office window toward Hilton Pond on 12 June, we noticed avian activity in nearby greenery. The vegetation in question was a tangle of Trumpet Creeper vines, and the birds--you might guess--were Ruby-throated Hummingbirds. Two hummers were trying very hard to get into a cluster of large blossoms (below), but the orange structures were not quite open.
All text, maps, charts & photos © Hilton Pond Center These were the first Trumpet Creeper flowers we'd noticed this spring. although it's possible some higher up in surrounding trees and more exposed to sunlight were already fully developed and making nectar. Was it a coincidence this first Trumpet Creeper inflorescence was appearing just about the time the year's Ruby-throated Hummingbirds were fledging and flying about? We don't think so.
All text, maps, charts & photos © Hilton Pond Center That RTHU feed on Trumpet Creeper is well-established, their long, thin bills and extensible tongues nicely adapted for probing and lapping up nectar from the vine's tubular and equally long, thin flowers. What's most interesting to us is this co-evolved timing, with Trumpet Creepers blossoming at just the right time for brooding females to have nectar to feed maturing chicks AND right when first fliers need a little boost post-fledging. Within a couple of days the closed flower tubes we noticed this week had opened and our local hummers were making frequent visits (below)--even though numerous sugar water feeders hung nearby.
All text, maps, charts & photos © Hilton Pond Center Ruby-throated Hummingbirds make good use of Trumpet Creeper nectar as an energy-rich carbohydrate source--and they acquire fat and protein by gleaning tiny invertebrates also attracted to the blossoms. At the same time, RTHU pick up pollen from one Trumpet Creeper flower and transport it to the next, assuring cross-pollination the vine needs to make seeds and propagate. This mutually beneficial relationship continues through spring and summer at Hilton Pond Center, with the last Trumpet Creeper flowers appearing in late August or early September--by which time many ruby-throats have already begun their southbound journeys. No, this symbiotic relationship isn't coincidental; it's exactly how nature works. All text, maps, charts & photos © Hilton Pond Center Don't forget to scroll down for lists of Hilton Pond supporters and of all birds banded and recaptured during the period. Photoshop image post-processing for this page employs |
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This spring we had our usual slow start to capturing new Ruby-throated Hummingbirds 
In our last installment 
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"This Week at Hilton Pond" is written and photographed by Dr. Bill Hilton Jr., executive director of Hilton Pond Center for Piedmont Natural History
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