Loading ...
Sorry, an error occurred while loading the content.
 

RE: [CALBIRDS] How widespread in CA is African Collared-Dove?

Expand Messages
  • Alvaro Jaramillo
    Adam I know exactly what you mean, this is why the time argument is the one that I am most confident in. Even with moderate selection against the pale birds,
    Message 1 of 16 , Sep 6, 2007
      Adam



      I know exactly what you mean, this is why the time argument is the one
      that I am most confident in. Even with moderate selection against the pale
      birds, there may not have been much time to dent their relative proportion
      yet. I mean we really are talking about a short time frame here as far as
      populations go. I would throw out the idea that this is a �recessive gene�
      that is a very specific situation which I think is unlikely in this case.
      The �risoria-like� phenotype is probably due to more than one gene, although
      this is a guess. But then again the property of a gene being recessive or
      dominant has nothing to do with shifting its proportions in a population, as
      you note, selection for or against the gene does. This is why blue eyes are
      not �bred out� when blue eyed people have kids with brown eyed people, the
      genes stay in the same proportions as they started in�unless there is
      selection against them. So I would argue that the pale birds we see are
      still an effect of the founder population, there just hasn�t been enough
      time for this genotype to be selected out, but my guess is that it will, or
      at least it�s proportion will stabilize at a lower number than it is now.



      By the way, here in Half Moon Bay, San Mateo County the Collared Dove is now
      the second most common dove in town after Mourning. There are more of them
      than Rock Pigeon, and at least in town more than Band-tailed Pigeons. It
      only took three years or so for this to happen. What is interesting is how
      these doves colonize a place. They seem to have nuclei of occurrence where
      they begin from, and then expand outwardly from there. It is not a broad
      front invasion, but disparate spots where they arrive, and then the
      intervening areas fill in. This is a rather different mode of expansion than
      most other bird expansions we have seen on the continent. This is certainly
      THE ornithological event of our birding lifetimes I would say, and we are
      all overlooking it. Has there ever been such a massive expansion in such a
      quick time of any bird on the continent? The next best avian expansion story
      that I can think of is Great-tailed Grackle, but that pales to what these
      doves are doing. I mean the entire continent has been taken over in a few
      years.



      Thanks for the note!



      Al



      Alvaro Jaramillo

      HYPERLINK "mailto:chucao@..."chucao@...

      Half Moon Bay, California



      Field Guides - Birding Tours Worldwide

      HYPERLINK "http://www.fieldguides.com"www.fieldguides.com

      _____

      From: Adam Winer [mailto:awiner@...]
      Sent: Thursday, September 06, 2007 9:45 PM
      To: Janet Leonard
      Cc: Kimball Garrett; Floyd Hayes; Calbirds; Alvaro Jaramillo
      Subject: Re: [CALBIRDS] How widespread in CA is African Collared-Dove?



      We've veered far off the e-mail lists here, but that assertion
      is mathematically false. Differential survival rates of
      genotypes would have a huge impact on the eventual proportions
      in a rapidly expanding population, for exactly the same reason that
      relatively small differences in per-year returns on monetary investments
      have an enormous effect over long periods.

      The issue is not whether pale individuals are producing enough
      to expand rapidly; it's whether they're producing enough to
      expand as rapidly as "standard" individuals. As with anything
      biological, many caveats apply - is this a recessive gene, if so are there
      heterozygote advantages, is it more or less advantageous in some
      habitats, etc. etc. But the basic point stands: were this a
      significantly deleterious gene, it should get blasted out of
      the gene pool in the course of the population explosion.

      (BTW, I think the core fallacy is "rapidly expanding" equals
      "low natural selection". Intensity of natural selection has
      nothing to do with overall population changes, and everything to
      do with relative reproductive success across genotypes.)

      -- Adam Winer



      On 9/6/07, Janet Leonard <HYPERLINK
      "mailto:jlleonar@..."jlleonar@...> wrote:

      Al-

      If a population is rapidly expanding, it must by definition be experiencing
      relatively low natural selection because more young survive and reproduce
      than in stable populations. Therefore, your argument about recessives not
      being weeded out makes sense.

      Jan Leonard

      Half Moon Bay



      ----- Original Message -----
      From: "Alvaro Jaramillo" <HYPERLINK "mailto:chucao%40coastside.net"
      \nchucao@...>
      To: "'Kimball Garrett'" <HYPERLINK "mailto:kgarrett%40nhm.org"
      \nkgarrett@...>; "'Floyd Hayes'"
      <HYPERLINK "mailto:floyd_hayes%40yahoo.com" \nfloyd_hayes@...>;
      "'Calbirds'" <HYPERLINK "mailto:calbirds%40yahoogroups.com" \n
      calbirds@yahoogroups.com>
      Sent: Thursday, September 06, 2007 8:28 PM
      Subject: RE: [CALBIRDS] How widespread in CA is African Collared-Dove?

      Kimball et al.

      Believe it or not I was thinking of sending a note along the same lines
      as what you wrote to ID frontiers, but now that the conversation is on here,
      I will add a few bits. I have been seeing a small proportion of the Half
      Moon Bay, San Mateo County population of Euro Collared-Dove which are pale,
      "risoria-like" but definitely E. Collared-Doves. I too have wondered about
      the significance of this, and have thought that it is not due to local
      releases, or hybridization but an aspect of the founder population in North
      America. I guess that the slightly different spin I would put on it is that
      the key elements may be the amazing expansion of the population and the
      short time it has taken for this to happen. Assuming that the founder
      population (Bahamas was it?) had pale Ringed T-D like birds, these genes
      will remain in the growing population in the same proportion as they started
      unless there is direct selection against them. My guess is that there is
      selection against them, but given the huge and quick expansion there just
      hasn't been that much time for this genotype to get weeded out from the
      general population. I am no population geneticist, but I wonder also if in
      an exponentially growing population which seems to have no immediate
      limitation in its population growth, if selection against a plumage type
      such as this is somehow lessened? So if we started with a founder population
      of let's say 5% pale birds, in such a short time (twenty years or so?) the
      expanding population may still have several percent pale birds involved. I
      would predict that as populations eventually stabilize, and higher levels of
      competition set in as the Collared-Dove niche is "filled" these pale birds
      will be weeded out by natural selection (differential predation on them,
      aggression from other doves, perhaps lesser ability to forage effectively
      due to this.etc). Like I said, I am no population geneticist, and if there
      is one out there who can say - Al you are full of it, I would be happy to
      learn from someone "in the know."

      Also, some additional information about Caribbean populations
      which I have been able to see while on tour. In the Lesser Antilles, the
      distribution of the dove is still expanding, and it appears that there may
      have been more than the one introduction to the Bahamas. For example the
      French Islands (Martinique and Guadeloupe) have huge populations of the
      dove, while the island in-between (Dominica) has very few. The French
      Islands are much more built up than Dominica, and this surely has an effect,
      but given that the French Islands have various other introduced species,
      while Dominica does not, suggests that the dove was introduced to the French
      Islands. Puerto Rico also has a population which may have been an
      independent introduction from the Bahamas birds. The birds in Puerto Rico
      are very mixed looking, patchy birds, pale birds etc. The general thought is
      that they are mixed populations between Euro Collared-Dove and "Ringed
      Turtle-Dove" however on the west side of the island where the population was
      pretty big, vocally birds were Eurasian Collared-Doves, although their
      appearance was variable. In Guadeloupe and Martinique, birds were more
      standard looking although pale birds were regularly seen.

      Regards

      Alvaro

      Alvaro Jaramillo

      HYPERLINK "mailto:HYPERLINK "mailto:chucao%40coastside.net"
      \nchucao@..."HYPERLINK "mailto:chucao%40coastside.net" \n
      chucao@...

      Half Moon Bay, California

      Field Guides - Birding Tours Worldwide

      HYPERLINK "HYPERLINK "http://www.fieldguides.com"
      \nhttp://www.fieldguides.com"HYPERLINK
      "http://www.fieldguides.com"www.fieldguides.com

      _____

      From: HYPERLINK "mailto:CALBIRDS%40yahoogroups.com"
      \nCALBIRDS@yahoogroups.com [mailto:HYPERLINK
      "mailto:CALBIRDS%40yahoogroups.com" \n CALBIRDS@yahoogroups.com] On Behalf
      Of Kimball Garrett
      Sent: Thursday, September 06, 2007 2:13 PM
      To: Floyd Hayes; Calbirds
      Subject: RE: [CALBIRDS] How widespread in CA is African Collared-Dove?

      Floyd (and Steve, Bruce, Alvaro, et al.):

      Thank you, Bruce, for clearing up the taxonomy. "Ringed Turtle-Dove" is
      indeed merely the domesticated form of African Collared-Dove,
      Streptopelia roseogrisea. There is (fortunately) a trend away from
      providing separate binomials for domesticated forms, though it is of
      interest that Linnaeus coined the binomial Streptopelia risoria (for
      "Ringed Turtle-Dove" or "Barbary Dove") before Streptopelia roseogrisea
      was named in 1857. I do have another, related, comment.

      >From my experience and that of many others with whom I've discussed
      this, occasional pale morphs are often seen with established Eurasian
      Collared-Dove (ECD) populations. In most cases these birds don't
      exactly match "classic" creamy-colored, small "Ringed Turtle-Doves"
      (RTDs), but they certainly differ from the expected phenotype of ECD.
      Years ago, one popular explanation was that these were RTDs that
      probably escaped from the same dove breeders who lost the ECDs (along,
      no doubt, with hybrids), thus supporting the notion that all of the
      various populations in California and neighboring regions resulted from
      local releases. Now, of course, it is clear that most of our ECD
      populations are part of the massive and rapid continent-wide expansion
      of this species, and that "local origin" can only be proved in a few
      cases.

      My suspicion, without the benefit of specimens or DNA sequences to back
      it up, is that a pale phenotype of ECD turns up occasionally in most
      populations, perhaps maintained as a recessive trait in the expanding
      populations. Perhaps this phenotype has its genetic origins in past
      captive breeding shenanigans (e.g. selective breeding for pale
      coloration, or cross-breeding with RTDs?). Or, perhaps, RTD genes were
      picked up through interbreeding as ECDs spread across North America
      (occasionally coming onto contact with escaped RTDs). But most likely
      it is just a rare morph of ECD. Quoting from Derek Goodwin's Pigeons and
      Doves of the World (Cornell Univ. Press, 1983): "Besides variation
      within the normal range [of Eurasian Collared-Dove]-, very pale
      individuals and others that are creamy buff like 'S. risoria' [RTD}
      occur quite frequently in Britain. There is no reason to suppose the
      mutants are of hybrid origin." Mention of pale creamy buff variants is
      also made in the BNA account by Christina Romagosa, and such morphs were
      noted by Bill Smith in some of the earliest populations established in
      the U. S.

      In any case, my point is that I'm not sure we should necessarily call
      these pale birds RTDs (or, more properly, domesticated forms of African
      Collared-Doves)-, absent a more thorough study. It seems likely that many
      or most of them are ECDs. If you encounter a pale bird, pay close
      attention to voice; the relatively clear 3-note cooing ("coo-COO-coo"-)
      of ECD is utterly different from the guttural "koo-kRRRRooo" of RTDs.

      Kimball

      Kimball L. Garrett
      Ornithology Collections Manager
      Natural History Museum of Los Angeles County
      900 Exposition Blvd.
      Los Angeles CA 90007
      (213) 763-3368
      (213) 746-2999 FAX
      HYPERLINK "mailto:HYPERLINK "mailto:kgarrett%25" \nkgarrett%HYPERLINK
      "http://40nhm.org" \n 40nhm.org"kgarrett@nhm.-org

      > -----Original Message-----
      > From: HYPERLINK
      "mailto:HYPERLINK "mailto:CALBIRDS%25" \nCALBIRDS%HYPERLINK
      "http://40yahoogroups.com"40yahoogroups.com"HYPERLINK
      "mailto:CALBIRDS%40yahoogroup-s.com" \n CALBIRDS@...
      [mailto:HYPERLINK "mailto:HYPERLINK" \nHYPERLINK
      "mailto:HYPERLINK "mailto:CALBIRDS%25" \nCALBIRDS%HYPERLINK
      "http://40yahoogroups.com"40yahoogroups.com"HYPERLINK
      "mailto:CALBIRDS%40yahoogroup-s.com" \n CALBIRDS@...] On
      Behalf
      > Of Floyd Hayes
      > Sent: Wednesday, September 05, 2007 10:40 AM
      > To: Calbirds
      > Subject: [CALBIRDS] How widespread in CA is African Collared-Dove?
      >
      > How widespread in CA is African Collared-Dove (aka
      > Ringed Turtle-Dove)-? Multiple African Collared-Doves
      > and Eurasian Collared-Doves showed up around the same
      > time in Napa Valley. I'm curious to know if African
      > Collared-Doves are turning up elsewhere in CA
      > alongside Eurasian Collared-Doves, and what the
      > implications would be for human assistance in the
      > spread of Eurasian Collared-Doves.
      >
      > Floyd Hayes
      > Hidden Valley Lake, CA

      No virus found in this incoming message.
      Checked by AVG Free Edition.
      Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
      3:18 PM

      No virus found in this outgoing message.
      Checked by AVG Free Edition.
      Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
      3:18 PM

      [Non-text portions of this message have been removed]

      Unsubscribe: mailto:HYPERLINK
      "mailto:CALBIRDS-unsubscribe%40yahoogroups.com"
      \nCALBIRDS-unsubscribe@yahoogroups.com
      Website: HYPERLINK "http://groups.yahoo.com/group/CALBIRDS"
      \nhttp://groups.yahoo.com/group/CALBIRDS
      Listowners: mailto:HYPERLINK "mailto:CALBIRDS-owner%40yahoogroups.com"
      \nCALBIRDS-owner@yahoogroups.com

      For vacation suspension of mail go to the website. Click on Edit My
      Membership and set your mail option to No Email. Or, send a blank email to
      these addresses:
      Turn off email delivery: mailto:HYPERLINK
      "mailto:CALBIRDS-nomail%40yahoogroups.com" \nCALBIRDS-nomail@yahoogroups.com
      Resume email delivery: mailto:HYPERLINK
      "mailto:CALBIRDS-normal%40yahoogroups.com" \nCALBIRDS-normal@yahoogroups.com

      Yahoo! Groups Links




      --
      No virus found in this incoming message.
      Checked by AVG Free Edition.
      Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
      3:18 PM





      No virus found in this incoming message.
      Checked by AVG Free Edition.
      Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
      3:18 PM


      No virus found in this outgoing message.
      Checked by AVG Free Edition.
      Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
      3:18 PM



      [Non-text portions of this message have been removed]
    • Janet Leonard
      Adam, Al et al. Relative reproductive success is a measure of natural selection; i.e. evolution through natural selection is measured as differential
      Message 2 of 16 , Sep 6, 2007
        Adam, Al et al.

        Relative reproductive success is a measure of natural selection; i.e. evolution through natural selection is measured as differential reproductive success (which includes likelihood of surviving to reproduce) of genotypes. That is, a genotype that produces more offspring is more fit (lower natural selection) than one that produces less. For the effects of expanding population size on evolution from a population genetics viewpoint see Kimura, M. 1995 PNAS and commentary by Damgaard 1996 in TREE. Certainly the presence of pale birds is derived from the founding population but if there were strong natural selection, they would quickly become rare. If it is a recessive trait they would never become extinct but they could quickly become rare.


        Jan Leonard



        Half Moon Bay

        ----- Original Message -----
        From: Adam Winer
        To: Janet Leonard
        Cc: Kimball Garrett ; Floyd Hayes ; Calbirds ; Alvaro Jaramillo
        Sent: Thursday, September 06, 2007 9:44 PM
        Subject: Re: [CALBIRDS] How widespread in CA is African Collared-Dove?


        We've veered far off the e-mail lists here, but that assertion
        is mathematically false. Differential survival rates of
        genotypes would have a huge impact on the eventual proportions
        in a rapidly expanding population, for exactly the same reason that
        relatively small differences in per-year returns on monetary investments
        have an enormous effect over long periods.

        The issue is not whether pale individuals are producing enough
        to expand rapidly; it's whether they're producing enough to
        expand as rapidly as "standard" individuals. As with anything
        biological, many caveats apply - is this a recessive gene, if so are there
        heterozygote advantages, is it more or less advantageous in some
        habitats, etc. etc. But the basic point stands: were this a
        significantly deleterious gene, it should get blasted out of
        the gene pool in the course of the population explosion.

        (BTW, I think the core fallacy is "rapidly expanding" equals
        "low natural selection". Intensity of natural selection has
        nothing to do with overall population changes, and everything to
        do with relative reproductive success across genotypes.)

        -- Adam Winer



        On 9/6/07, Janet Leonard <jlleonar@...> wrote:
        Al-

        If a population is rapidly expanding, it must by definition be experiencing
        relatively low natural selection because more young survive and reproduce
        than in stable populations. Therefore, your argument about recessives not
        being weeded out makes sense.

        Jan Leonard

        Half Moon Bay



        ----- Original Message -----
        From: "Alvaro Jaramillo" <chucao@...>
        To: "'Kimball Garrett'" <kgarrett@...>; "'Floyd Hayes'"
        <floyd_hayes@...>; "'Calbirds'" < calbirds@yahoogroups.com>
        Sent: Thursday, September 06, 2007 8:28 PM
        Subject: RE: [CALBIRDS] How widespread in CA is African Collared-Dove?

        Kimball et al.

        Believe it or not I was thinking of sending a note along the same lines
        as what you wrote to ID frontiers, but now that the conversation is on here,
        I will add a few bits. I have been seeing a small proportion of the Half
        Moon Bay, San Mateo County population of Euro Collared-Dove which are pale,
        "risoria-like" but definitely E. Collared-Doves. I too have wondered about
        the significance of this, and have thought that it is not due to local
        releases, or hybridization but an aspect of the founder population in North
        America. I guess that the slightly different spin I would put on it is that
        the key elements may be the amazing expansion of the population and the
        short time it has taken for this to happen. Assuming that the founder
        population (Bahamas was it?) had pale Ringed T-D like birds, these genes
        will remain in the growing population in the same proportion as they started
        unless there is direct selection against them. My guess is that there is
        selection against them, but given the huge and quick expansion there just
        hasn't been that much time for this genotype to get weeded out from the
        general population. I am no population geneticist, but I wonder also if in
        an exponentially growing population which seems to have no immediate
        limitation in its population growth, if selection against a plumage type
        such as this is somehow lessened? So if we started with a founder population
        of let's say 5% pale birds, in such a short time (twenty years or so?) the
        expanding population may still have several percent pale birds involved. I
        would predict that as populations eventually stabilize, and higher levels of
        competition set in as the Collared-Dove niche is "filled" these pale birds
        will be weeded out by natural selection (differential predation on them,
        aggression from other doves, perhaps lesser ability to forage effectively
        due to this.etc). Like I said, I am no population geneticist, and if there
        is one out there who can say - Al you are full of it, I would be happy to
        learn from someone "in the know."

        Also, some additional information about Caribbean populations
        which I have been able to see while on tour. In the Lesser Antilles, the
        distribution of the dove is still expanding, and it appears that there may
        have been more than the one introduction to the Bahamas. For example the
        French Islands (Martinique and Guadeloupe) have huge populations of the
        dove, while the island in-between (Dominica) has very few. The French
        Islands are much more built up than Dominica, and this surely has an effect,
        but given that the French Islands have various other introduced species,
        while Dominica does not, suggests that the dove was introduced to the French
        Islands. Puerto Rico also has a population which may have been an
        independent introduction from the Bahamas birds. The birds in Puerto Rico
        are very mixed looking, patchy birds, pale birds etc. The general thought is
        that they are mixed populations between Euro Collared-Dove and "Ringed
        Turtle-Dove" however on the west side of the island where the population was
        pretty big, vocally birds were Eurasian Collared-Doves, although their
        appearance was variable. In Guadeloupe and Martinique, birds were more
        standard looking although pale birds were regularly seen.

        Regards

        Alvaro

        Alvaro Jaramillo

        HYPERLINK "mailto:chucao@..." chucao@...

        Half Moon Bay, California

        Field Guides - Birding Tours Worldwide

        HYPERLINK "http://www.fieldguides.com"www.fieldguides.com

        _____

        From: CALBIRDS@yahoogroups.com [mailto: CALBIRDS@yahoogroups.com] On Behalf
        Of Kimball Garrett
        Sent: Thursday, September 06, 2007 2:13 PM
        To: Floyd Hayes; Calbirds
        Subject: RE: [CALBIRDS] How widespread in CA is African Collared-Dove?

        Floyd (and Steve, Bruce, Alvaro, et al.):

        Thank you, Bruce, for clearing up the taxonomy. "Ringed Turtle-Dove" is
        indeed merely the domesticated form of African Collared-Dove,
        Streptopelia roseogrisea. There is (fortunately) a trend away from
        providing separate binomials for domesticated forms, though it is of
        interest that Linnaeus coined the binomial Streptopelia risoria (for
        "Ringed Turtle-Dove" or "Barbary Dove") before Streptopelia roseogrisea
        was named in 1857. I do have another, related, comment.

        >From my experience and that of many others with whom I've discussed
        this, occasional pale morphs are often seen with established Eurasian
        Collared-Dove (ECD) populations. In most cases these birds don't
        exactly match "classic" creamy-colored, small "Ringed Turtle-Doves"
        (RTDs), but they certainly differ from the expected phenotype of ECD.
        Years ago, one popular explanation was that these were RTDs that
        probably escaped from the same dove breeders who lost the ECDs (along,
        no doubt, with hybrids), thus supporting the notion that all of the
        various populations in California and neighboring regions resulted from
        local releases. Now, of course, it is clear that most of our ECD
        populations are part of the massive and rapid continent-wide expansion
        of this species, and that "local origin" can only be proved in a few
        cases.

        My suspicion, without the benefit of specimens or DNA sequences to back
        it up, is that a pale phenotype of ECD turns up occasionally in most
        populations, perhaps maintained as a recessive trait in the expanding
        populations. Perhaps this phenotype has its genetic origins in past
        captive breeding shenanigans (e.g. selective breeding for pale
        coloration, or cross-breeding with RTDs?). Or, perhaps, RTD genes were
        picked up through interbreeding as ECDs spread across North America
        (occasionally coming onto contact with escaped RTDs). But most likely
        it is just a rare morph of ECD. Quoting from Derek Goodwin's Pigeons and
        Doves of the World (Cornell Univ. Press, 1983): "Besides variation
        within the normal range [of Eurasian Collared-Dove]-, very pale
        individuals and others that are creamy buff like 'S. risoria' [RTD}
        occur quite frequently in Britain. There is no reason to suppose the
        mutants are of hybrid origin." Mention of pale creamy buff variants is
        also made in the BNA account by Christina Romagosa, and such morphs were
        noted by Bill Smith in some of the earliest populations established in
        the U. S.

        In any case, my point is that I'm not sure we should necessarily call
        these pale birds RTDs (or, more properly, domesticated forms of African
        Collared-Doves)-, absent a more thorough study. It seems likely that many
        or most of them are ECDs. If you encounter a pale bird, pay close
        attention to voice; the relatively clear 3-note cooing ("coo-COO-coo"-)
        of ECD is utterly different from the guttural "koo-kRRRRooo" of RTDs.

        Kimball

        Kimball L. Garrett
        Ornithology Collections Manager
        Natural History Museum of Los Angeles County
        900 Exposition Blvd.
        Los Angeles CA 90007
        (213) 763-3368
        (213) 746-2999 FAX
        HYPERLINK "mailto:kgarrett% 40nhm.org"kgarrett@nhm.-org

        > -----Original Message-----
        > From: HYPERLINK
        "mailto:CALBIRDS%40yahoogroups.com" CALBIRDS@...
        [mailto:HYPERLINK
        "mailto:CALBIRDS%40yahoogroups.com" CALBIRDS@...] On
        Behalf
        > Of Floyd Hayes
        > Sent: Wednesday, September 05, 2007 10:40 AM
        > To: Calbirds
        > Subject: [CALBIRDS] How widespread in CA is African Collared-Dove?
        >
        > How widespread in CA is African Collared-Dove (aka
        > Ringed Turtle-Dove)-? Multiple African Collared-Doves
        > and Eurasian Collared-Doves showed up around the same
        > time in Napa Valley. I'm curious to know if African
        > Collared-Doves are turning up elsewhere in CA
        > alongside Eurasian Collared-Doves, and what the
        > implications would be for human assistance in the
        > spread of Eurasian Collared-Doves.
        >
        > Floyd Hayes
        > Hidden Valley Lake, CA

        No virus found in this incoming message.
        Checked by AVG Free Edition.
        Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
        3:18 PM

        No virus found in this outgoing message.
        Checked by AVG Free Edition.
        Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
        3:18 PM

        [Non-text portions of this message have been removed]

        Unsubscribe: mailto:CALBIRDS-unsubscribe@yahoogroups.com
        Website: http://groups.yahoo.com/group/CALBIRDS
        Listowners: mailto:CALBIRDS-owner@yahoogroups.com

        For vacation suspension of mail go to the website. Click on Edit My
        Membership and set your mail option to No Email. Or, send a blank email to
        these addresses:
        Turn off email delivery: mailto:CALBIRDS-nomail@yahoogroups.com
        Resume email delivery: mailto:CALBIRDS-normal@yahoogroups.com

        Yahoo! Groups Links


        --
        No virus found in this incoming message.
        Checked by AVG Free Edition.
        Version: 7.5.485 / Virus Database: 269.13.8/993 - Release Date: 9/6/2007
        3:18 PM







        [Non-text portions of this message have been removed]
      • Rusty Scalf
        ... It seems that these Doves have leap-frogged the San Francisco Basin. I was in Lee Vining recently and would estimate the Collared/Mourning ratio at about 3
        Message 3 of 16 , Sep 6, 2007
          > By the way, here in Half Moon Bay, San Mateo County the Collared Dove

          > is now the second most common dove in town after Mourning. There are
          > more of them than Rock Pigeon

          It seems that these Doves have leap-frogged the San Francisco Basin.

          I was in Lee Vining recently and would estimate the Collared/Mourning
          ratio at about 3 to 1. And they're certainly all over the San Joaquin
          Valley.

          If they're that common on the San Mateo Coast, I wonder why this is not
          the case in Oakland and Berkeley. They're about, but nothing like what
          you describe.

          Rusty Scalf
        • dsuddjian@aol.com
          In a message dated 9/6/2007 11:57:21 PM Pacific Daylight Time, rfs_berkeley@yahoo.com writes: If they re that common on the San Mateo Coast, I wonder why this
          Message 4 of 16 , Sep 7, 2007
            In a message dated 9/6/2007 11:57:21 PM Pacific Daylight Time,
            rfs_berkeley@... writes:

            If they're that common on the San Mateo Coast, I wonder why this is not
            the case in Oakland and Berkeley. They're about, but nothing like what
            you describe.

            Maybe it is a matter of scale. In Santa Cruz County we are seeing the pattern
            of expanding nuclei that Al mentions in the cities of Santa Cruz and
            Watsonville, but while the species is becoming increasingly widespread here it remains
            patchy and much more sporadic in other parts of the county. There are still
            significant areas of likely habitat where one would have a hard time finding
            ECD on order.

            Interestingly, ECD was present in a nucleus area in western Santa Cruz for
            several years before the regional invasion hit central CA a few years ago. It
            remained quite local in that nucleus for years and only exhibited the strong
            expanding pattern within western Santa Cruz coincident with the species'
            broadscale arrival in central CA two to three years ago. But in Watsonville there
            apparently were no nuclei before the regional invasion reached SCZ, but the
            expanding nuclei pattern then developed there. My impression is that the local
            pattern of nuclear explosion (if you'll pardon me) is fueled by the ongoing
            broadscale influx.

            David Suddjian
            Capitola, CA



            ************************************** Get a sneak peek of the all-new AOL at
            http://discover.aol.com/memed/aolcom30tour


            [Non-text portions of this message have been removed]
          • Floyd Hayes
            I don t doubt that there are pale Eurasian Collared-Doves resembling African Collared-Doves, but I was familiar with both of these species from the Caribbean
            Message 5 of 16 , Sep 7, 2007
              I don't doubt that there are pale Eurasian
              Collared-Doves resembling African Collared-Doves, but
              I was familiar with both of these species from the
              Caribbean and I'm quite confident both are present in
              the Napa Valley. On 2 January I saw about five of each
              (the pale ones aren't rare), with the Eurasian
              Collared-Doves giving three-noted calls and the
              presumed African Collared-Doves giving two-noted
              calls. I just posted photos at:

              http://www.geocities.com/floyd_hayes/collared-doves.html

              Incidentally, in contrast with the North American
              mainland, Eurasian Collared-Doves are spreading very
              slowly in the Caribbean. Despite an initial release in
              the northern Bahamas (New Providence in 1974) it is
              still relatively rare in the central and southern
              Bahamas (my brother and I photographed San Salvador's
              2nd in 2004). Unknown to most people, the birds were
              definitely released (well documented) on Guadeloupe in
              1976 (Barre et al., Pitirre 9(2):2-4, 1996), from
              which they slowly spread northward, only recently
              arriving in the Virgin Islands (one record, a bird I
              photographed in 2003), and they also spread southward,
              arriving in Dominica in 1987 and Martinique in 1994. I
              don't think they have been recorded yet on any islands
              to the south of Martinique except Trinidad, far to the
              south, where I photographed one (origin unknown) in
              2000.

              Floyd Hayes
              Hidden Valley Lake, CA



              ____________________________________________________________________________________
              Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out.
              http://answers.yahoo.com/dir/?link=list&sid=396545469
            • Kimball Garrett
              [Note: I m not the listowner, but it s my opinion that Streptopelia doves are part of the California avifauna, and therefore fair game for discussion on this
              Message 6 of 16 , Sep 7, 2007
                [Note: I'm not the listowner, but it's my opinion that Streptopelia
                doves are part of the California avifauna, and therefore fair game for
                discussion on this list serve; I agree that discussions of population
                genetics may not qualify, however.]

                Two quick points:

                (1) Floyd surely is seeing African Collared-Doves (= "Barbary" or
                "Ringed Turtle-" Doves), and I didn't mean to imply in my previous
                messages that pale variant ECDs were the only possible explanation for
                what he was seeing. Domestic African Collared-Doves (ACDs or RTDs)
                escape very frequently, and of course central Los Angeles used to have a
                population that was even "ABA Countable" in the 1960s and 1970s (and had
                been established by the 1940s or earlier). Various morphs of ACDs are
                still released at the sorts of celebrations and public events that
                require liberation of large numbers of totally discombobulated domestic
                birds, and individuals escape all the time.

                (2) Regarding the discussion of ECDs being largely absent from most
                large urban areas such as the main San Francisco Bay metropolis, I think
                this is partly a matter of habitat -- this species generally doesn't do
                well in heavily urban areas. ECDs are absent or rare (tiny, very
                localized populations) in most of the greater Los Angeles urban area as
                well. This species depends almost entirely on grain -- in agricultural
                areas, weedy rural areas, industrial areas with grain mills, railroad
                right-of-ways in grain-producing regions, etc. Just about its only
                option in highly urbanized areas is commercial bird seed at feeders, and
                apparently there aren't enough feeders to sustain ECD populations in
                most highly urbanized areas.

                I'd much rather be out looking at Arctic Warblers than blabbing on about
                feral doves....

                Kimball

                Kimball L. Garrett
                Ornithology Collections Manager
                Natural History Museum of Los Angeles County
                900 Exposition Blvd.
                Los Angeles CA 90007
                (213) 763-3368
                (213) 746-2999 FAX
                kgarrett@...


                > -----Original Message-----
                > From: CALBIRDS@yahoogroups.com [mailto:CALBIRDS@yahoogroups.com] On
                Behalf
                > Of Floyd Hayes
                > Sent: Friday, September 07, 2007 10:59 AM
                > To: Calbirds
                > Subject: [CALBIRDS] RE: How widespread in CA is African Collared-Dove?
                >
                > I don't doubt that there are pale Eurasian
                > Collared-Doves resembling African Collared-Doves, but
                > I was familiar with both of these species from the
                > Caribbean and I'm quite confident both are present in
                > the Napa Valley.
              Your message has been successfully submitted and would be delivered to recipients shortly.