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--Apple-Mail-15-987837078 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi, Nancy, and thanks for your various messages and for your interest and question here -- the latter has no easy answer, since the mudflats and their possible foods for the peeps are so diverse and complex and ever-changing. The bloodworm industry finally got licensed and theoretically controlled and regulated by provincial fisheries people quite a few years ago (15?). Someone in the Yarmouth office of the N.S. Fisheries Dept. used to be the bureaucrat with the jurisdiction and all the data. And I am long out of date on monitoring the catches each year, numbers of diggers, and which beaches are legal vs. taboo/fallow each year. Old studies at Acadia Univ. showed that the bloodworm diggers greatly modify the flats physically over large areas, and only some of the flats fauna were studied at the time, like the bloodworms themselves and the Corophium, which I now call mud shrimps. The recolonization by the shrimps is one thing that requires a bit of time, but then the habitat is then changed to such an extent that the sandpipers have a much harder time of detecting the shrimps, thus they are less available. Your question was quite logical, in thinking that fewer bloodworms, which eat mud shrimps among other things, might mean an increase in those shrimps. But the physical change to the sediment seems to be very important. The food webs on the flats are very complex, and we tend to forget about the fishes that move in and out with the times with opposite timing to sandpipers. Remember too that all the relationships are on the tidal clock, with four tides per 24-hours- and-25-minutes. Major players in the food webs are microscopic diatoms (shelled algae) that migrate up and down with every tidal change, many critters that feed on diatoms (mud snails, mud shrimps, sandpipers themselves at night esp. on moonlit nights, etc.), a huge diversity of marine worms (most are deposit-feeders, less spp. are carnivorous), many bivalves and other snails & slugs, huge numbers of filter-feeding hydrozoans (relatives of jellyfish & anemones), many crustaceans like sand shrimps, sand isopods, hermit crabs, other crabs, etc. etc. Cheers from Jim in Wolfville. On 19-Jul-13, at 8:38 PM, Nancy P Dowd wrote: > Hi Jim > > Thank you for that simplified summary of the sandpiper waves of > southward migration. > > I do not know the details of the bloodworm trade. But would their > removal for bait possibly result in the opposite effect and leave > more prey (I.e. Corophium and other small arthropods) available for > the peeps without the worms feeding on them instead? Other things > may be more influential in their needing more time to fatten up. > > Just a thought. > > Nancy > > Sent from my iPhone > > On 2013-07-19, at 4:24 PM, "James W. Wolford" > <jimwolford@eastlink.ca> wrote: > >>> Date: July 19, 2013 4:20:14 PM ADT >>> To: Nature BNS <nature@blomidonnaturalists.ca>, Diana Hamilton >>> <dhamilto@mta.ca>, Sherman Boates <boatesjs@gov.ns.ca>, Sue >>> Abbott <sabbott@bsc-eoc.org>, Julie Paquet <Julie.Paquet@ec.gc.ca> >>> Subject: [ValleyNature] Evangeline Beach shorebirds etc., July >>> 19/13 (a bit long) >>> >>> JULY 19, 2013 - EVANGELINE BEACH -- This morning was quite rainy >>> and overcast, but by 11:30 a.m. (high tide was 10 a.m.) the rain >>> was very light, almost a drizzle, which gradually lightened more >>> and then quit while I did a vigil from my car in the canteen >>> parking lot (car with driver-side facing Cape Blomidon (north). >>> Compared with yesterday's bright and blinding sunlight, today the >>> visibility was perfect, with the flying small shorebirds (peeps) >>> very easy to see against the light gray sky. The ebbing water/ >>> flats edge was quite close to me when I started, versus much >>> further out/advanced at my start yesterday. Thus during my watch >>> from 11:30 a.m. to 12:18 p.m., the flats went from quite narrow >>> to fairly broad, but nowhere near how far the water would >>> eventually recede by low tide, which would have been three hours >>> later. >>> >>> Here is the report from my vigil today: Today I saw a total of >>> 658 "peeps" or small shorebirds (prob. mostly semipalmated >>> sandpipers), which is about 200 more than seen yesterday. All of >>> these were flying along or parallel to the shore, from east to >>> west, and none that I watched landed at all, heading out of sight >>> to the west (toward the mouth of the Cornwallis River). Flock >>> sizes, in order from 11:30 a.m. to 12:08 p.m., were: 25 + 20 + 35 >>> + 25 + 350 + 20 + 60 + 3 + 20 + 20 + 20 + 20 + 30 + 10. Very >>> probably I missed some peeps, since, like yesterday, the first >>> small flock occurred just when I arrived. >>> >>> Other birds seen were 9 double-crested cormorants, 18 herring >>> gulls, 5 great black-backed gulls, and 2 immature bald eagles. >>> >>> A surprise seen fairly close to shore was a SEAL, very probably a >>> harbour seal, seen only briefly and distantly. >>> >>> I ended my vigil at 12:18 p.m. >>> --------------------------- >>> >>> FURTHER GENERAL INFO' ON OUR MIGRANT SHOREBIRDS here in the Minas >>> Basin Important Bird Area: >>> >>> For those who don't know, I will summarize the season for the >>> south-bound migrant shorebirds at this site (especially >>> semipalmated sandpipers). After mostly wintering in South >>> America, most of them take a different route on their migration >>> north through Spring to arrive in the Low Arctic, west of Hudson >>> Bay across to Alaska, where they court, nest, and raise >>> juveniles. Female adults incubate the eggs, then the male raises >>> the chicks, while the female can recover & fatten up & migrate >>> south before the others. The earliest southbound migrants arrive >>> from late June to (mostly) mid-July. The next wave of migrants >>> is mostly males, who have by then abandoned the independent >>> juveniles in the north and migrated south. Finally the third >>> wave, largely naive juveniles, show up here (these three "waves" >>> are herein greatly oversimplified). All of them are dependent on >>> the nutritious mudflats for fattening up for that long, non-stop- >>> over-the-water, flight to northern South America (Suriname). >>> Thus the season here is a long one, from early to mid-July to >>> well into September and later to October. During those many >>> weeks, flocks are constantly arriving while others are departing, >>> when conditions are right for long flights. (Also consider the >>> common sense that says, if the semi's were not really good at >>> this, natural selection would have weeded out this migratory >>> route.) Individual semi' sandpipers have been thought to spend >>> 10 to 14 days here in fattening up, but there is some concern >>> that this length of stay could be longer than previously. One >>> possible reason of many is that commercial digging of baitworms/ >>> bloodworms (Glycera) here for bait for sport-fishing in eastern >>> U.S. results in some of the prey animals like mud shrimps >>> becoming not only less abundant but also less available to the >>> semi' sandpipers. >>> >>> Here I will invite comments from Julie Paquet of Can. Wildl. >>> Service, Sherman Boates of N.S. Dept. of Nat. Resources, and >>> especially Diana Hamilton of Mount Allison University, who has >>> had a team studying all of this for quite a few years, with many >>> publications. One of the things they have discovered is that the >>> diet of the semi' sandpipers is much more diverse than previously >>> thought. >>> >>> Additional important perspective is that these shorebirds have >>> been showing gradual population declines during recent decades, >>> and the reasons are poorly understood, I think. Quality of >>> nesting habitats and overwintering habitats are big questions, in >>> addition to all of the stop-over spots like ours here. The local >>> mudflats are extremely biodiverse and incredibly productive >>> (think of the salt-marsh sediment and Grand Pre agricultural >>> crops on the dykelands, which used to be tidal marshes). >>> ------------------------- >>> Cheers from Jim in Wolfville. >>> _______________________________________________ >>> Nature mailing list >>> Nature@blomidonnaturalists.ca >>> http://blomidonnaturalists.ca/mailman/listinfo/ >>> nature_blomidonnaturalists.ca >> --Apple-Mail-15-987837078 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=US-ASCII <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; "> Hi, Nancy, and thanks for your various messages and for your interest = and question here -- the latter has no easy answer, since the mudflats = and their possible foods for the peeps are so diverse and complex and = ever-changing. The bloodworm industry finally got licensed and = theoretically controlled and regulated by provincial fisheries people = quite a few years ago (15?). Someone in the Yarmouth office of the = N.S. Fisheries Dept. used to be the bureaucrat with the jurisdiction and = all the data. And I am long out of date on monitoring the catches = each year, numbers of diggers, and which beaches are legal vs. = taboo/fallow each year. <div><br></div><div>Old studies at Acadia = Univ. showed that the bloodworm diggers greatly modify the flats = physically over large areas, and only some of the flats fauna were = studied at the time, like the bloodworms themselves and the Corophium, = which I now call mud shrimps. The recolonization by the shrimps is = one thing that requires a bit of time, but then the habitat is then = changed to such an extent that the sandpipers have a much harder time of = detecting the shrimps, thus they are less = available.</div><div><br></div><div>Your question was quite logical, in = thinking that fewer bloodworms, which eat mud shrimps among other = things, might mean an increase in those shrimps. But the physical = change to the sediment seems to be very important. The food webs = on the flats are very complex, and we tend to forget about the fishes = that move in and out with the times with opposite timing to sandpipers. = Remember too that all the relationships are on the tidal clock, = with four tides per 24-hours-and-25-minutes. = </div><div><br></div><div>Major players in the food webs are = microscopic diatoms (shelled algae) that migrate up and down with every = tidal change, many critters that feed on diatoms (mud snails, mud = shrimps, sandpipers themselves at night esp. on moonlit nights, etc.), a = huge diversity of marine worms (most are deposit-feeders, less spp. are = carnivorous), many bivalves and other snails & slugs, huge numbers = of filter-feeding hydrozoans (relatives of jellyfish & anemones), = many crustaceans like sand shrimps, sand isopods, hermit crabs, other = crabs, etc. etc.</div><div><br></div><div>Cheers from Jim in = Wolfville.</div><div><br><div><div>On 19-Jul-13, at 8:38 PM, Nancy P = Dowd wrote:</div><br class=3D"Apple-interchange-newline"><blockquote = type=3D"cite"><div>Hi Jim</div><div><br></div><div>Thank you for that = simplified summary of the sandpiper waves of southward = migration. </div><div><br></div><div>I do not know the details of = the bloodworm trade. But would their removal for bait possibly result in = the opposite effect and leave more prey (I.e. Corophium and other small = arthropods) available for the peeps without the worms feeding on them = instead? Other things may be more influential in their needing more time = to fatten up. </div><div><br></div><div>Just a = thought. </div><div><br></div><div>Nancy<br><br>Sent from my = iPhone</div><div><br>On 2013-07-19, at 4:24 PM, "James W. Wolford" = <<a = href=3D"mailto:jimwolford@eastlink.ca">jimwolford@eastlink.ca</a>> = wrote:<br><br></div><blockquote type=3D"cite"><div><div><blockquote = type=3D"cite"><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; "><font face=3D"Helvetica" = size=3D"3" color=3D"#000000" style=3D"font: 12.0px Helvetica; color: = #000000"><b>Date: </b></font><font face=3D"Helvetica" size=3D"3" = style=3D"font: 12.0px Helvetica">July 19, 2013 4:20:14 PM = ADT</font></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; "><font face=3D"Helvetica" = size=3D"3" color=3D"#000000" style=3D"font: 12.0px Helvetica; color: = #000000"><b>To: </b></font><font face=3D"Helvetica" size=3D"3" = style=3D"font: 12.0px Helvetica">Nature BNS <<a = href=3D"mailto:nature@blomidonnaturalists.ca">nature@blomidonnaturalists.c= a</a>>, Diana Hamilton <<a = href=3D"mailto:dhamilto@mta.ca">dhamilto@mta.ca</a>>, Sherman Boates = <boatesjs@gov.ns.ca>, = Sue Abbott <<a = href=3D"mailto:sabbott@bsc-eoc.org">sabbott@bsc-eoc.org</a>>, Julie = Paquet <<a = href=3D"mailto:Julie.Paquet@ec.gc.ca">Julie.Paquet@ec.gc.ca</a>></font>= </div><div style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: = 0px; margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" = color=3D"#000000" style=3D"font: 12.0px Helvetica; color: = #000000"><b>Subject: </b></font><font face=3D"Helvetica" size=3D"3" = style=3D"font: 12.0px Helvetica"><b>[ValleyNature] Evangeline Beach = shorebirds etc., July 19/13 (a bit long)</b></font></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; min-height: 14px; "><br></div> <div style=3D"margin-top:= 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font = face=3D"Helvetica" size=3D"3" style=3D"font: 12.0px Helvetica"><b>JULY = 19, 2013 - EVANGELINE BEACH </b>-- This morning was quite<b> rainy and = overcast, but</b> by 11:30 a.m. (high tide was 10 a.m.) the rain was = very light, almost a drizzle, which gradually lightened more and then = quit while<b> I did a vigil from my car </b>in the canteen parking lot = (car with driver-side facing Cape Blomidon (north). Compared with = yesterday's bright and blinding sunlight, today the <b>visibility was = perfect</b>, with the flying small shorebirds (peeps) very easy to see = against the light gray sky. The ebbing water/flats edge was quite = close to me when I started, versus much further out/advanced at my start = yesterday. Thus during my watch from 11:30 a.m. to 12:18 p.m., the = flats went from quite narrow to fairly broad, but nowhere near how far = the water would eventually recede by low tide, which would have been = three hours later.</font></div><div style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal = normal normal 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica"><b>Here is the report from my vigil today: </b>Today I = saw a total of <b>658 "peeps"</b> or small shorebirds (prob. mostly = semipalmated sandpipers), which is about 200 more than seen = yesterday. All of these were flying along or parallel to the = shore, from east to west, and none that I watched landed at all, heading = out of sight to the west (toward the mouth of the Cornwallis = River). Flock sizes, in order from 11:30 a.m. to 12:08 p.m., were: = 25 + 20 + 35 + 25 + 350 + 20 + 60 + 3 + 20 + 20 + 20 + 20 + 30 + = 10. <b>Very probably I missed some peeps, since</b>, like = yesterday, the first small flock occurred just when I = arrived.</font></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica"><b>Other birds seen</b> were 9 double-crested = cormorants, 18 herring gulls, 5 great black-backed gulls, and 2 immature = bald eagles.</font></div><div style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica">A surprise seen fairly close to shore was <b>a SEAL, = very probably a harbour seal</b>, seen only briefly and = distantly.</font></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica">I ended my vigil at 12:18 p.m.</font></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica">---------------------------</font></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; font: normal normal normal 12px/normal Helvetica; = min-height: 14px; "><br></div><div style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font = face=3D"Helvetica" size=3D"3" style=3D"font: 12.0px = Helvetica"><b>FURTHER GENERAL INFO' ON OUR MIGRANT SHOREBIRDS here in = the Minas Basin Important Bird Area:</b></font></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; font: normal normal normal 12px/normal Helvetica; = min-height: 14px; "><br></div><div style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font = face=3D"Helvetica" size=3D"3" style=3D"font: 12.0px Helvetica">For those = who don't know, I will summarize the <b>season for the south-bound = migrant shorebirds</b> at this site (especially semipalmated = sandpipers). After mostly wintering in South America, most of them = take a different route on their migration north through Spring to arrive = in the Low Arctic, west of Hudson Bay across to Alaska, where they = court, nest, and raise juveniles. Female adults incubate the eggs, = then the male raises the chicks, while the female can recover & = fatten up & migrate south before the others. The earliest = southbound migrants arrive from late June to (mostly) mid-July. = The next wave of migrants is mostly males, who have by then abandoned = the independent juveniles in the north and migrated south. Finally = the third wave, largely naive juveniles, show up here (these three = "waves" are herein greatly oversimplified). All of them are = dependent on the nutritious mudflats for fattening up for that long, = non-stop-over-the-water, flight to northern South America = (Suriname). Thus<b> the season here is a long one</b>, from early = to mid-July to well into September and later to October. During = those many weeks, flocks are constantly arriving while others are = departing, when conditions are right for long flights. (Also = consider the common sense that says, if the semi's were not really good = at this, natural selection would have weeded out this migratory = route.) Individual semi' sandpipers have been thought to spend 10 = to 14 days here in fattening up, but there is some concern that this = length of stay could be longer than previously. One possible = reason of many is that commercial digging of baitworms/bloodworms = (<i>Glycera</i>) here for bait for sport-fishing in eastern U.S. results = in some of the prey animals like mud shrimps becoming not only less = abundant but also less available to the semi' = sandpipers.</font></div><div style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica"><b>Here I will invite comments</b> from Julie Paquet = of Can. Wildl. Service, Sherman Boates of N.S. Dept. of Nat. Resources, = and especially Diana Hamilton of Mount Allison University, who has had a = team studying all of this for quite a few years, with many = publications. One of the things they have discovered is that the = diet of the semi' sandpipers is much more diverse than previously = thought.</font></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><font face=3D"Helvetica" size=3D"3" style=3D"font: = 12.0px Helvetica">Additional important perspective is that these = shorebirds have been showing gradual <b>population declines</b> during = recent decades, and the reasons are poorly understood, I think. = Quality of <b>nesting habitats and overwintering habitats</b> are big = questions, in addition to all of the stop-over spots like ours = here. The local mudflats are extremely biodiverse and incredibly = productive (think of the salt-marsh sediment and Grand Pre agricultural = crops on the dykelands, which used to be tidal = marshes). </font></div><div style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; "><font face=3D"Helvetica" = size=3D"3" style=3D"font: 12.0px Helvetica">------------------------- = </font></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; font: normal normal normal = 12px/normal Helvetica; min-height: 14px; ">Cheers from Jim in = Wolfville.</div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; = ">_______________________________________________</div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Nature mailing list</div><div style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a = href=3D"mailto:Nature@blomidonnaturalists.ca">Nature@blomidonnaturalists.c= a</a></div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; "><a = href=3D"http://blomidonnaturalists.ca/mailman/listinfo/nature_blomidonnatu= ralists.ca">http://blomidonnaturalists.ca/mailman/listinfo/nature_blomidon= naturalists.ca</a></div> = </blockquote></div><br></div></blockquote></blockquote></div><br></div></b= ody></html>= --Apple-Mail-15-987837078--
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