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

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

Expand Messages
  • 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 1 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 2 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 3 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 4 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 5 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.