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A River of Hummingbirds

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  • Steve Bouricius
    Hi Folks, The migration of hummingbirds continues on the Western Slope but there are obvious changes in the age classes of the birds compared to only a week
    Message 1 of 1 , Aug 14, 2005
      Hi Folks,

      The migration of hummingbirds continues on the Western Slope but there are obvious changes in the age classes of the birds compared to only a week ago.  A look at this week's captures compared with those of last week is revealing.  This weekend Debbie and I caught 161 hummingbirds of four species.  We banded 130 birds and logged 31 captures of previously banded birds.  As many as 39 data fields are recorded for the birds depending upon species, age and sex.  Newly banded birds include:

      [AHY = after hatch year or adult, HY = hatch year or juvenile, M = male, F = female, BCHU = Black-chinned Hummingbird, RUHU = Rufous Hummingbird, CAHU = Calliope Hummingbird, BTLH = Broad-tailed Hummingbird]

      BCHU    AHY M          20
      BCHU    AHY F           10
      BCHU    HY   M          42
      BCHU    HY   F            15            [87]

      RUHU    AHY M          0
      RUHU    AHY F           8
      RUHU    HY   M          18
      RUHU    HY   F             5            [31]

      CAHU    AHY M          0
      CAHU    AHY F           1
      CAHU    HY   M           5
      CAHU    HY   F            3             [9]

      BTLH      HY   F           2             
                      HY   M          1            [3]         {130}

      Among the 31 recaptures was an adult male Black-chinned which we banded as an adult on 5-19-01, so he is at least 5 years of age, possibly older.  We also recaptured a local bird which we banded as a nestling on June 18 in our orchard, tree #A2x7.  The hen which raised this bird is now tending a second brood nest only 16 feet away in tree #A3x7.  While she was still feeding this nestling on her first brood nest, she built the second nest, laid eggs, and began incubating, thus tending two nests at one time in an easily defensible space.  Amazing eh, but I digress....

      Taking a quick look at the numbers of last weekend's adult males compared to this weekend, 40 Black-chins banded then, now number only 20 banded.  Last week we banded 13 male Rufous, none this weekend, although we did see one.  Last week we banded 4 male Calliope, none this weekend, although we did see one.  Last week we saw one male Broad-tailed, not caught, this week none.

      A look at the changes in juvenile male and juvenile female numbers is also revealing.  From last week's 24 HY male Black-chinned, we banded 42 this weekend.  Last week we caught no HY male Calliopes but banded 5 this weekend.  So, the numbers show differences in the timing of migration between the species as well as age and sex classes.  The hatch year birds are now migrating in greater numbers.

      The point of all this, for those who have read this far   :>), is not to throw out numbers to be stored away, but to provide a demographic snapshot of hummingbird migration which shows that adult males migrate through first, followed by adult females and juvenile males, with juvenile females generally later.  When you look at the birds in your yard it might seem to be much as it has been all summer, with the same individuals using the same places day after day.  But there is in fact, a dynamic movement, a daily turnover of individuals.  Think of it as a river of hummingbirds flowing through the region.  It is only through banding that we can document the ebb and flow.

      Steve Bouricius
      Palisade

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      On 8-10-05 Steve Bouricius wrote:

      Hi Folks,

      Hummingbird activity has been brisk here lately.  In addition to the flower gardens the hummers are now using about forty feeders and 3+ gallons of sugar water a day.  It seems to be a very good year here for adult male Rufous and Calliope hummingbirds.  Since Saturday we have banded 145 new birds but it is a small fraction of the birds to come through the yard each day.  Our six traps cover only six of the forty feeders.  Banding has shown us that there is a dramatic daily turnover of birds in migration now.  Some stay a few minutes, others an hour or so, a few stay for two or three days, then move on south.  The numbers below give a picture of what we are catching but I know we miss many birds, especially Calliopes and juvenile Black-chins because they more often use flowers rather than the feeders where our traps are.  Rufous's are probably over represented because as one is trapped, another promptly takes it's place to dominate a trap feeder and is soon captured.  Also, several Black-chinned females are still tending nests in our orchard and they use food sources there, mostly insects and alfalfa flowers, so they too are surely under counted.

      [AHY is after hatch year or adult, HY is hatch year or juvenile, M is male, F is female, BCHU is Black-chinned Hummingbird, RUHU is Rufous Hummingbird, CAHU is Calliope Hummingbird, BTLH is Broad-tailed Hummingbird]:

      BCHU    AHY M          40
      BCHU    AHY F           10
      BCHU    HY   M          24
      BCHU    HY   F             5               [79]

      RUHU    AHY M          13
      RUHU    AHY F           17
      RUHU    HY   M          18
      RUHU    HY   F             8             [56]

      CAHU    AHY M          4
      CAHU    AHY F           3
      CAHU    HY   M           0
      CAHU    HY   F            2              [9]

      BTLH      HY   F           1              [1]

      Besides the new birds, we have had many interesting recaptures of previously banded birds.  On Sunday we caught an adult male Black-chinned, band number R00795.  This bird was banded as an adult on July 26, 2000, so he is at least six years old.  This fellow was also recaptured here on July 20, 2002, and May 15, 2004.  Like many of the BCHU males recaptured at this time, I suspect he lives in the region but not necessarily on or near our farm.

      On Saturday we hosted 26 kids and parents from the Palisade 4-H club to learn about hummingbirds, hummingbird behavior and nesting, how to attract them and keep them safe, and about our banding studies.  It was a great group of kids, especially savvy about animals and wildlife.  They asked so many good questions, some I didn't have a good answer for. But every question reveals something more that needs to be known, and there is so much yet to learn about hummingbirds.  Everyone got a Colorado bird checklist, a book on hummingbirds, and hummingbird feeders provided by Colorado's Perky-Pet Company were given away.

      Deb and I have also been banding birds at our cabin in Peaceful Valley, on the east slope south of Rocky Mountain National Park (255 miles from Palisade).  The  hummers are at peak numbers around 8500 ft. elevation on the east slope, with mostly BTLH (~85%) and RUHU, and a few CAHU.   We banded 208 birds there recently.  With our neighbor's help the birds use about 5-8 gallons a day now, with many thousands of birds.  We are using 18 feeders there and the neighbors have 13 feeders.  When we can't make it over for a couple weeks, our feeders run out and the good neighbors have to buy more sugar.  :>)    With ten catchers I think we could keep twenty bird banders busy every day from Jul 15-Aug 15.  Scott Rashid and Fred and Tena Engleman are banding hummers about 20 miles north in the Estes Park/RMNP area but so far Deb and I have not caught any of their birds, or vice versa.  I think it's a needle in a haystack thing.  We'll be banding there again next weekend with Scott and a new trainee joining us.

      Now's the time to have all your feeders out, clean and fresh, and to be on the lookout for rarities.  We hope you'll give us a call to help document these rarities which may signal important trends.  Last January 12th, I posted to WSBN and to COBirds the prediction:  "So what's next on our [state] list? I think Allen's is most likely but a White-eared is a good possibility too. I can hardly wait to see what spring will bring."  The "good possibility" is still attending feeders eight weeks after being found in Durango June 19th, and more than four weeks after being banded.  Hmmm.  We just KNOW there's an Allen's Hummingbird (or a Green-breasted Mango) around here somewhere.

      Is anybody else excited about hummingbirds?  We sure are!

      Steve and Debbbie
      Palisade, CO



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      Steve & Debbie Bouricius
      3412 C Road
      Palisade, CO 81526
      970-434-5918
      Hummingbird Orchards
      ....Banding and Research Station
      USGS Bird Banding Laboratory permit #23198
      CDOW Scientific Collections permit #05BD834
      NABC certified master hummingbird banders
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