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HUMMINGBIRD HIGHS

By the time mid-October arrives, we know the chances are slim to none for getting any more Ruby-throated Hummingbirds at Hilton Pond Center; of the 3,020 we've captured locally since 1984, only 34 have been banded after 30 September. Regardless, we don't put away our hummer traps and banding tools each autumn--we HAVE been fortunate to capture two Rufous Hummingbirds in past Novembers--but we do take time to assess our most-recent ruby-throat banding efforts. We're happy to report that 2004 was our best-ever year for ruby-throats at Hilton Pond--210 hummers banded!--so in more than one way we're still on a "hummingbird high."

All text, charts & photos © Hilton Pond Center

After a very disappointing 2003 hummer banding season, we weren't sure what to expect for 2004, but we got off to a rapid start. Our first arrival was a returning male on 8 April that had been banded as a hatch-year bird on 30 August 2002 and was also recaptured last year. Compared to the average he was a tad late--our first male hummer usually appears around 4 or 5 April--and the record early date is 27 March 1991. The first unbanded ruby-throat this year was even later--an adult male on 9 April--with the first adult female showing up two days later on 11 April. During our 21 years of hummingbird banding, females have tended to follow spring males by about a week or ten days, although the earliest adult female trapped at Hilton Pond was on 8 April 2002.

Click HERE for larger view of chart above

As shown by the "Rate of New Bandings" chart (above), this year's hummers (red line) were indeed plentiful. Things exploded around mid-July when young birds began to show up at feeders and traps, driving our banding totals to the highest levels ever by that time of year. Activity dropped back slightly around 20 July, but a steady influx of new birds kept pace with 1995 (dark blue line)--our previous record year with 197 total birds banded; we eventually tied this record on 19 September and surpassed it the next day. After that things really began to slow down. In more than half the years since 1984 we have banded at least one ruby-throat in October--our late date at Hilton Pond Center is 18 October 1986--but our last new bird in 2004 was on 28 September, with the last hummer seen on 4 October.

The first fledgling Ruby-throated Hummingbirds of 2004 were two males banded on 21 June. Our record early day for young birds is 9 June (in 1994 and 2000), but in almost half of all past years the first fledglings weren't captured until the first week in July--or later.

The main reason 2004 hummingbird banding was so successful was because capture rates for all age-sex classes were well above average (see table above). In fact, we tied our record for hatch-year females at 60--set in 1995--and came fairly close to records for the other three age-sex classes. As always, hatch-year males (top photo) made up the largest subset, and adult males the smallest, indicating that newly fledged males must be expendable and that older Ruby-throated Hummingbird males are relatively rare.

Click HERE for larger view of chart above

The red trend line on the "New Captures" chart (above) shows that despite an inexplicably poor showing in 2003, the average number of hummingbirds banded over the 21-year period continues to increase. As always, it's hard to know exactly why the trend is upward, or why 2004 turned into a record-setting year. Although we don't keep track of net-hours or how much time we devote to watching our pull-string hummingbird traps from March through October, we suspect our annual effort through the years has been relatively constant. It's curious, however, that this year we caught more hummers than usual in mist nets. On average over 21 years we've snared 19.9% of our ruby-throats in nets and 80.1% in various traps; this year, a whopping 36% hit the nets. Nearly half (47%) the hatch-year males were netted rather than trapped, compared to 19.1% in all years to date.

Click HERE for larger view of chart above

There are many variables that could affect hummingbird numbers, including weather, local habitat change over the past two decades, and availability of natural nectar sources. And there's always the possibility we were away from Hilton Pond when a passing front or other conditions brought lots of hummingbirds. For example, on the chart (above) that shows when we banded ruby-throats in 2004 or first encountered banded birds from previous years, 29 May shows as a pretty important day with seven bandings and nine new re-traps. Likewise, a four-day span in mid-July was quite productive with 25 ruby-throats banded on the 14th (8 birds), 16th (9--our highest one-day total for 2004), and 17th (8). Who knows what could have happened on 15 July when we were gone all day for an out-of-town meeting--or while we were at a GLOBE conference in Colorado for eight days the last week of July.

To us, that ANY hummers come back is remarkable, considering that many young Ruby-throated Hummingbirds quickly die from various causes AND those surviving the round-trip to the tropics and back may have to fly as much as 5,000 miles. So now, as our hummers spend the winter in the more favorable climate of Mexico and Central America, we have no choice but to wait for them to return to Hilton Pond in 2005 to see if we can have an even better "hummingbird high" during NEXT year's banding season.

(Hmmm, we take that back. What we're REALLY going to do is jet off to Costa Rica right after Christmas to see if we can find any of our Hilton Pond hummers on their wintering grounds. There are still a few spots available for our inexpensive eight-day expeditions; 2 November is the deadline to sign up, so check out the trip description at Operation RubyThroat/GLOBE Expeditions if you're interested in sharing a mid-winter "hummingbird high" in the tropics. Remember, we're talking about December and January--when it's bound to be cold, wet, and miserable across most of North America!)

All text, charts & photos © Hilton Pond Center

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SPECIES BANDED THIS WEEK:
Eastern Phoebe--1
Palm Warbler--1
Common Yellowthroat--1 *
Yellow-rumped Warbler--4
Red-eyed Vireo--1
Scarlet Tanager--1
Swainson's Thrush--1
Wood Thrush--1
Brown Thrasher--1

* = New species for 2004

WEEKLY BANDING TOTAL
9 species
12 individuals

YEARLY BANDING TOTAL
(2004)
60 species
1,810 individuals

BANDING GRAND TOTAL
(since 28 June 1982)
123 species
45,115 individuals