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Hummingbird conservation and perches on feeders

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  • Judy Hoy
    Hi all, Since hummingbirds are migrating back north from their wintering areas south of the United States, I think this topic is the most important at this
    Message 1 of 5 , Mar 23, 2006
      Hi all,

      Since hummingbirds are migrating back north from their wintering areas
      south of the United States, I think this topic is the most important at
      this time. Sorry that this is so long, but the problem takes a bit of
      explaining and so far, I have not gotten anyone to do anything to save
      the hummingbirds from unnecessary death or save eggs and young from
      dying while the mother bird is too hypothermic to get back to the nest.
      What we need is more people complaining about the problem. I hope that
      will help anyway.
      In spring of 1983, my husband, a wildlife biologist, observed
      something wrong with Rufous Hummingbirds sitting on perches, feeding at
      our hummingbird feeders in the cold morning hours before sunrise. He
      watched as a male hummer sat on the perch and took several long sips of
      the ice-cold fluid. Then the bird fluffed up, slowly tipped over
      backward and fell from the perch to the ground. He rushed out and
      picked it up, finding that it was still breathing, but very cold. He
      warmed the bird by holding it in his cupped hands and blowing his warm
      breath onto the bird. After ten or fifteen minutes, the bird had warmed
      enough so that it had regained its ability to fly normally and it was
      released. Since I am a wildlife rehabber, I followed the bird around
      from a distance after it was released, watching it through binoculars
      to make sure it was alright. It appeared to be completely fine with no
      after effects from its mishap. After finding and warming three more
      birds the next day, two hanging upside down from the perch and one on
      the ground, we removed the perches from all the feeders. My husband
      continued to watch the feeders early in the morning to see what effect
      having no perches would have on the feeding birds. He found that the
      hummingbirds had no trouble feeding while flying and would take a few
      sips of the icy fluid then fly to their favorite branch to digest it,
      then back for a few more sips and back to the branch. No more birds
      were found on the ground under the feeders and no more problems were
      observed. Meanwhile, I checked my rehab records for hummingbird
      injuries and found that I had gotten predominantly Rufous Hummingbirds,
      predominantly early morning cat or dog bites, predominantly early
      spring. That seemed like an ominous pattern.
      This was the scenario that we concluded. Hummingbirds normally hover
      when feeding. They also normally fly from flower to flower, getting
      only a small amount of fluid from each sip. Even early risers like the
      Rufous won’t get chilled with that scenario. Enter bird feeders, which
      provide large volumes of superchilled fluid to the birds coming to feed
      before sunrise. Humans add perches to allow easier viewing.
      Hummingbirds that perch while feeding are not generating heat energy
      needed to warm the fluid they ingest, and they are eating larger than
      normal (what they would get from flowers) helpings of the ice cold
      sugar water. If a hummingbird sips a cropful of cold fluid, it lowers
      their body temperature as much as ten degrees, or more if the outside
      temperature is in the thirtys. After two cropfuls without flying to
      generate heat, the birds temperature will be low enough to cause
      serious hypothermia and the bird can no longer control its muscles, so
      it is not able to fly. We concluded that the Rufous Hummingbirds, by
      feeding in early morning, are more likely than other hummingbird
      species to suffer Perch Hypothermia (PH) as I named the phenomenon. PH
      has been reported being seen by many other people, to several other
      species of hummer, especially Ruby-throated Hummingbirds. Any
      hummingbird that becomes so hypothermic that it can not maintain normal
      flight or falls to the ground is apt to end up dead, often as cat or
      corvid food. People usually do not get up early enough to view the
      hummingbirds sitting on the perches between 4:30 or 5:00 and sunrise,
      so most do not observe PH when it happens to the birds. As the
      hypothermic hummers are usually snatched up and eaten by Crows, Magpies
      or cats, no evidence is left by the time people get up.
      In 1986, after researching the problem and collecting reports of other
      observations of PH, I launched a crusade to inform the public about the
      problem. I wrote to ornithologists, outdoor magazines, bird magazines
      and the local newspapers. I was ridiculed and many said that PH could
      not possibly happen. Even after connecting with hummingbird researchers
      in Texas who had done controlled studies that showed that Ruby-throated
      Hummingbirds’ flight muscles were adversely affected by sitting
      motionless on a perch while consuming cold fluid, some people claimed
      that I had no scientific proof of the PH "hypothesis." Hypothermia has
      long been a proven physical fact, it has not been a hypothesis for
      decades. Actually, hypothermia was quite well understood by ice age
      cave man.
      Unfortunately, after twenty years of trying to have the problem of PH
      addressed, the companies that make hummingbird feeders have not removed
      the perches or put warnings on the boxes that having perches on the
      feeders can have adverse effects on hummers feeding on ice cold sugar
      water. More and more people have built homes in western states and put
      up hummingbird feeders with perches. In that time Rufous Hummingbirds
      have gone from being the most populous species of hummingbird in the
      western United States to being placed on Audubon’s species of special
      concern list because of precipitous population decline.
      I am hoping that others might have advice on how to get something done
      about this unnecessary (and according to the US Fish and Wildlife
      Service, who did nothing) illegal killing of hummingbirds. Anything man
      made that deliberately causes the deaths of migratory birds is illegal.
      Putting up feeders for hummingbirds with perches on them is deliberate.

      Thank you for any help you can provide.


      Judy Hoy
      Bitterroot Wildlife Rehabilitation Center
      2858 Pheasant Lane
      Stevensville, MT 59870 USA
    • Jay Greenberg
      Thank you for this very interesting and informative post. I have been interested in bird conservation for over 10 years, but I was completely unaware of the
      Message 2 of 5 , Mar 24, 2006
        Thank you for this very interesting and informative post.  I have been interested in bird conservation for over 10 years, but I was completely unaware of the problem.  I think that if enough people know about it and want something done, then manufacturers of feeders will be pressured to change.  I will try to help by spreading the word, especially by forwarding your message to other list servers.  By the way, if you could get video documentation of the phenomenon, it might help to convince people.

        E-mail Signature Jay Greenberg <conservationist@...>
        Rochester, NY


        Judy Hoy wrote:
        Hi all,

        Since hummingbirds are migrating back north from their wintering areas south of the United States, I think this topic is the most important at this time. Sorry that this is so long, but the problem takes a bit of explaining and so far, I have not gotten anyone to do anything to save the hummingbirds from unnecessary death or save eggs and young from dying while the mother bird is too hypothermic to get back to the nest. What we need is more people complaining about the problem. I hope that will help anyway.
        In spring of 1983, my husband, a wildlife biologist, observed something wrong with Rufous Hummingbirds sitting on perches, feeding at our hummingbird feeders in the cold morning hours before sunrise. He watched as a male hummer sat on the perch and took several long sips of the ice-cold fluid. Then the bird fluffed up, slowly tipped over backward and fell from the perch to the ground. He rushed out and picked it up, finding that it was still breathing, but very cold. He warmed the bird by holding it in his cupped hands and blowing his warm breath onto the bird. After ten or fifteen minutes, the bird had warmed enough so that it had regained its ability to fly normally and it was released. Since I am a wildlife rehabber, I followed the bird around from a distance after it was released, watching it through binoculars to make sure it was alright. It appeared to be completely fine with no after effects from its mishap. After finding and warming three more birds the next day, two hanging upside down from the perch and one on the ground, we removed the perches from all the feeders. My husband continued to watch the feeders early in the morning to see what effect having no perches would have on the feeding birds. He found that the hummingbirds had no trouble feeding while flying and would take a few sips of the icy fluid then fly to their favorite branch to digest it, then back for a few more sips and back to the branch. No more birds were found on the ground under the feeders and no more problems were observed. Meanwhile, I checked my rehab records for hummingbird injuries and found that I had gotten predominantly Rufous Hummingbirds, predominantly early morning cat or dog bites, predominantly early spring. That seemed like an ominous pattern.
        This was the scenario that we concluded. Hummingbirds normally hover when feeding. They also normally fly from flower to flower, getting only a small amount of fluid from each sip. Even early risers like the Rufous won’t get chilled with that scenario. Enter bird feeders, which provide large volumes of superchilled fluid to the birds coming to feed before sunrise. Humans add perches to allow easier viewing. Hummingbirds that perch while feeding are not generating heat energy needed to warm the fluid they ingest, and they are eating larger than normal (what they would get from flowers) helpings of the ice cold sugar water. If a hummingbird sips a cropful of cold fluid, it lowers their body temperature as much as ten degrees, or more if the outside temperature is in the thirtys. After two cropfuls without flying to generate heat, the birds temperature will be low enough to cause serious hypothermia and the bird can no longer control its muscles, so it is not able to fly. We concluded that the Rufous Hummingbirds, by feeding in early morning, are more likely than other hummingbird species to suffer Perch Hypothermia (PH) as I named the phenomenon. PH has been reported being seen by many other people, to several other species of hummer, especially Ruby-throated Hummingbirds. Any hummingbird that becomes so hypothermic that it can not maintain normal flight or falls to the ground is apt to end up dead, often as cat or corvid food. People usually do not get up early enough to view the hummingbirds sitting on the perches between 4:30 or 5:00 and sunrise, so most do not observe PH when it happens to the birds. As the hypothermic hummers are usually snatched up and eaten by Crows, Magpies or cats, no evidence is left by the time people get up.
        In 1986, after researching the problem and collecting reports of other observations of PH, I launched a crusade to inform the public about the problem. I wrote to ornithologists, outdoor magazines, bird magazines and the local newspapers. I was ridiculed and many said that PH could not possibly happen. Even after connecting with hummingbird researchers in Texas who had done controlled studies that showed that Ruby-throated Hummingbirds’ flight muscles were adversely affected by sitting motionless on a perch while consuming cold fluid, some people claimed that I had no scientific proof of the PH "hypothesis." Hypothermia has long been a proven physical fact, it has not been a hypothesis for decades. Actually, hypothermia was quite well understood by ice age cave man.
        Unfortunately, after twenty years of trying to have the problem of PH addressed, the companies that make hummingbird feeders have not removed the perches or put warnings on the boxes that having perches on the feeders can have adverse effects on hummers feeding on ice cold sugar water. More and more people have built homes in western states and put up hummingbird feeders with perches. In that time Rufous Hummingbirds have gone from being the most populous species of hummingbird in the western United States to being placed on Audubon’s species of special concern list because of precipitous population decline.
        I am hoping that others might have advice on how to get something done about this unnecessary (and according to the US Fish and Wildlife Service, who did nothing) illegal killing of hummingbirds. Anything man made that deliberately causes the deaths of migratory birds is illegal. Putting up feeders for hummingbirds with perches on them is deliberate.

        Thank you for any help you can provide.


        Judy Hoy
        Bitterroot Wildlife Rehabilitation Center
        2858 Pheasant Lane
        Stevensville, MT 59870 USA
      • Judy Hoy
        Dear Jay, I did not have a video camera, and still don t. Also, we have never had perches on our feeders since 1983. I did do some tests with two permanently
        Message 3 of 5 , Mar 24, 2006
          Dear Jay,

          I did not have a video camera, and still don't. Also, we have never had
          perches on our feeders since 1983. I did do some tests with two
          permanently injured unreleasable flightless Rufous Hummingbirds on two
          different occasions. I fed one warmed sugar water first when I took it
          out, to see if it acted any different with warm fluid. It remained
          alert, sleek and interested in its surroundings. Then after just one
          cropful of 42 degree sugar water, the bird fluffed up and would not
          respond to stimuli. I have a slide of the fluffed up bird with its eyes
          closed. As soon as I took it back into the house and warmed it up, it
          was fine. That day was overcast and the outdoor temperature was 45
          degrees. After the bird was warm and drank several cropfuls of warm
          sugar water to make sure it was healthy and warm, I repeated the
          experiment. I got the same results. It took only one drink of cold
          fluid while sitting still outside on a cool day for it to become
          hypothermic. This temperature and the temperature of the fluid (42
          degrees) was much warmer than the outdoor temperature or the sugar
          water in outside feeders on cold spring mornings between 32 and 38
          degrees. I repeated the test with another unreleasable Rufous
          Hummingbird a year or so later. The outside temperature was 49 degrees,
          with overcast sky and no sun. The sugar water was 43 degrees. I got the
          same results, only it took two drinks of the cold fluid for that bird
          to fluff and become unresponsive. Again, after being taken into the
          house and warmed, it was fine. I had to eventually euthanize both birds
          since they were unreleasable.

          More importantly, the study by Chai, P., Cang, A.C., Dudley, R. (1998)
          Flight thermogenesis and energy conservation in hovering hummingbirds,
          The Journal of Experimental Biology, Vol. 201, pages 963-968. showed
          that the birds were adversely affected. That study was and may still be
          available on the web. Doug Altshuler, who also worked on this study,
          stated to me in a letter, "I agree with you that perch hypothermia
          could be a problem of significant concern for hummingbird conservation."

          Unfortunately, there have not been very many Rufous Hummingbirds coming
          to our feeders in recent years, so our chance of getting a video, if I
          went and bought a camera, would not be very good now. The adults that
          are still alive often hover above the perches on other peoples feeders
          and never land to drink. I am hearing many more reports of
          Ruby-throated Hummingbirds being found hypothermic now than I do Rufous.

          Thank you for spreading the word.
          Judy

          Judy Hoy
          Stevensville, MT USA
        • Brent Ortego
          I feed hundreds of hummingbirds of 8 species during the winter with temperatures frequently near freezing and this has never been a problem. Nor has it been a
          Message 4 of 5 , Mar 24, 2006
            I feed hundreds of hummingbirds of 8 species during the winter with temperatures frequently near freezing and this has never been a problem. Nor has it been a problems for the hundreds of birders that feed hummers during the winter. Hummingbird researchers and hummingbird enthusiasts corresponding on Humnet-L and Humband listserves have discussed your previous posts and the general conclusion it was not of value.

            Brent Ortego

            -----Original Message-----
            From: birdconservation@yahoogroups.com
            [mailto:birdconservation@yahoogroups.com]On Behalf Of Judy Hoy
            Sent: Friday, March 24, 2006 12:05 PM
            To: birdconservation@yahoogroups.com
            Subject: Re: [birdconservation] Hummingbird conservation and perches on
            feeders


            Dear Jay,

            I did not have a video camera, and still don't. Also, we have never had
            perches on our feeders since 1983. I did do some tests with two
            permanently injured unreleasable flightless Rufous Hummingbirds on two
            different occasions. I fed one warmed sugar water first when I took it
            out, to see if it acted any different with warm fluid. It remained
            alert, sleek and interested in its surroundings. Then after just one
            cropful of 42 degree sugar water, the bird fluffed up and would not
            respond to stimuli. I have a slide of the fluffed up bird with its eyes
            closed. As soon as I took it back into the house and warmed it up, it
            was fine. That day was overcast and the outdoor temperature was 45
            degrees. After the bird was warm and drank several cropfuls of warm
            sugar water to make sure it was healthy and warm, I repeated the
            experiment. I got the same results. It took only one drink of cold
            fluid while sitting still outside on a cool day for it to become
            hypothermic. This temperature and the temperature of the fluid (42
            degrees) was much warmer than the outdoor temperature or the sugar
            water in outside feeders on cold spring mornings between 32 and 38
            degrees. I repeated the test with another unreleasable Rufous
            Hummingbird a year or so later. The outside temperature was 49 degrees,
            with overcast sky and no sun. The sugar water was 43 degrees. I got the
            same results, only it took two drinks of the cold fluid for that bird
            to fluff and become unresponsive. Again, after being taken into the
            house and warmed, it was fine. I had to eventually euthanize both birds
            since they were unreleasable.

            More importantly, the study by Chai, P., Cang, A.C., Dudley, R. (1998)
            Flight thermogenesis and energy conservation in hovering hummingbirds,
            The Journal of Experimental Biology, Vol. 201, pages 963-968. showed
            that the birds were adversely affected. That study was and may still be
            available on the web. Doug Altshuler, who also worked on this study,
            stated to me in a letter, "I agree with you that perch hypothermia
            could be a problem of significant concern for hummingbird conservation."

            Unfortunately, there have not been very many Rufous Hummingbirds coming
            to our feeders in recent years, so our chance of getting a video, if I
            went and bought a camera, would not be very good now. The adults that
            are still alive often hover above the perches on other peoples feeders
            and never land to drink. I am hearing many more reports of
            Ruby-throated Hummingbirds being found hypothermic now than I do Rufous.

            Thank you for spreading the word.
            Judy

            Judy Hoy
            Stevensville, MT USA




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          • Judy Hoy
            Dear Brent, Thank you for your observations of winter feeding hummingbirds. I have long suspected that our birds are being affected by some kind of toxin in
            Message 5 of 5 , Mar 24, 2006
              Dear Brent,

              Thank you for your observations of winter feeding hummingbirds. I have
              long suspected that our birds are being affected by some kind of toxin
              in the air here in spring that affects their ability to maintain heat
              and energy normally, resulting in being more susceptible to PH. Some
              areas have a high rate of PH at their feeders in spring, but no problem
              in the fall. You are verifying that there is not a problem where you
              are in winter, presumably in Texas.

              I do not belong to Humnet-L or Humband, so did not see the discussions.
              I am unclear as to what was not of value, our observations of PH, the
              Texas controlled study or the discussion itself. David Bird wrote an
              article in Birdwatchers Digest about hypothermia in general regarding
              many bird species, including hummingbirds. Quite a few people wrote
              letters to Birdwatchers Digest saying that they had observed PH at
              their feeders in Ruby-throated Hummingbirds. All reports of PH here and
              in eastern U.S. were in the spring. I also said that the people who had
              observed PH here in Western Montana observed the problem in Rufous
              Hummingbirds only. I saw reports in magazines about people observing PH
              in Ruby-throated hummers, but only in spring or early summer, not in
              the fall or winter. With more discussion, we may be able to determine a
              more definite pattern. Thank you for your post.

              Judy


              On Friday, March 24, 2006, at 11:57 AM, Brent Ortego wrote:

              > I feed hundreds of hummingbirds of 8 species during the winter with
              > temperatures frequently near freezing and this has never been a
              > problem. Nor has it been a problems for the hundreds of birders that
              > feed hummers during the winter. Hummingbird researchers and
              > hummingbird enthusiasts corresponding on Humnet-L and Humband
              > listserves have discussed your previous posts and the general
              > conclusion it was not of value.
              >
              > Brent Ortego
              >
              > -----Original Message-----
              > From: birdconservation@yahoogroups.com
              > [mailto:birdconservation@yahoogroups.com]On Behalf Of Judy Hoy
              > Sent: Friday, March 24, 2006 12:05 PM
              > To: birdconservation@yahoogroups.com
              > Subject: Re: [birdconservation] Hummingbird conservation and perches on
              > feeders
              >
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