The Changing Seasons the Big Picture
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THE CHANGING SEASONS The BigPicture Brian L. Sullivan in EastCoast records a recentby-product of ing distribution,and even the difficult ques- their expandingbreeding distribution in tionsof birds'conservation in a landscape PRBO-ConservationScience NorthAmerica? What otherspecies might that seems ever more stressed. we expectto find associatedwith thesesys- On some level, it is difficult to conceive 4990Shoreline Highway tems(such as Ash-throated Flycatcher), and that birds'distribution and migratorypat- what accounts for the differences in their terns are substantiallydifferent than they StinsonBeach, California 94970 numbers and distribution in the East? Have were200 yearsago, or even2000 years ago. therebeen changes in recentyears in mete- Buta carefulreading of evenjust one'sown (email:[email protected]) orological conditions that might affect regionalreports--spanning back just a half migratorymovements of thesespecies? The century--isenough to broadenour imagina- pagesof thisjournal brim with questionsof tion of how thingsmust have been. Sixty thisnature; it is refreshingthat we havethe yearsago, much of LongIsland was farm- pastautumn, I wasstruck by howmuch freedomhere to ask questionsfor which land and indeed much of the East Coast, 'n.wereading as a communitytheregionalof birders reportscontinue fromthisto there may be no easyanswers or evenscien- especiallyin theSouth, was free from "devel- learn about avian distribution and abun- tificallytestable hypotheses. opment."One hundredyears ago, Cahfor- dance,and strucktoo by the value and Whateverour relationshipto the many nia waslargely wilderness; and Ivory-billed potentialuses of thesereports. I find it ornithologicalpuzzles that appearin this Woodpeckerswere still to beseen in suitable remarkable that after more than two cen- journal,there is littledoubt that we arerap- habitatin severalstates. Two hundred years turiesof North Americanbird study,the idly becomingmore astutebirders in this ago,contiguous forests stretched from the efforts of North American Birds contributors hemisphereand that we asa groupare also AtlanticCoast almost to the Mississippi continue to illuminate little-known corners increasinglysanguine about the importance River; the West was not yet "won,"and of the continent and its offshore waters. of the documentation of our time in the nativeprairies burned annually The paths With eachseasods migration, we re-evaluate field. As to "rarities,"birders in the Ameri- of migratorybirds and movements of mam- the suppositionsput forthby themany pre- cashave minds now moreopen than ever: mal herdswere not alteredthen by vast vious authors of this column. What new possibilitiesforraerly thought extremely expansesof suburhia,telecommunications questionswill arise,and what questions remoteare now known to beregular. In the towers,skyscrapers, highways, or lightpol- seem to have been answered? Which regionalreports, records of Siberianspecies lution. Surelythese anthropogenic influ- specieswill continueto declineor expand, stretchfrom Hawaii to Alaska,from Califor- enceshave greatly altered bird movements to irruptor withdraw?And what might the nia to the Midwest and the East--almost all anddistribution and are in partresponsible underlyingcauses of thesedynamics be? As of themfound by birderswho anticipated for thenew patterns we readabout here. our abilitiesto predictappearances of out- theirappearances. Tropical pelagic species Butas the natural history of NorthAmeri- of-rangespecies based on weatherforecasts were moved to the Great Lakes after a hurri- canbirds has changed, so too, radically, have improve,is our understandingof the con- cane-and birders knew where and how to thenatural historians. The growing numbers nection between birds' movements and look for them. California birders found two of birdersin North America,the advancesin weather systemsalso improving? Will new shearwaterspecies this season,one bird identificationthat continueto be pio- Novemberlow-pressure systems tracking from the North Atlantic, one from the South neered,and the truly new age of information- toward the Northeast again produce PacificOcean--and were fully preparedto sharingclearly influence the permanent record extrafimital Cave Swallows--or were the identify and documentboth. Outlandish of American bird distribution. One hundred flightsof thepast decade tied to factorsthat hummingbirdsout of range?Only the Arc- yearsago, who could haveforeseen, for haveless to dowith weather patterns per se tic regionsseem out of boundsfor these instance,the coordinatedteams of GYeatLakes than with populationdynamics? And will birds,whose appearances are catalogued and birders,linked by cell phonesand pagers, thosesame systemscontinue to disperse admirablydocumented by an armyof back- scouringtheir areasfor hurricane-driven waywardwestern migrants and vagrants to yard feeder-enthusiasts,almost a birding petrelsand storm-petrels? A hundred years the eastern United States and Canadian Mar- subculturein itself. In thesepages one can ago,hurricanes were horrible, unpredictable itimes(and even on towardEurope)? detect scoresof patternsamid the over shocksto coastalcommunities; our satellites Evenas we confirm,annually, that certain 100,000words of seasonalsummary. I con- now witness their movementsfrom birth, meteorologicalevents do havean influence lessthat I oncegleaned these pages for oftenthousands of milesfrom our shores,to on bird movements,still more questions imagesof rareand unusual birds, and 1 still extra-tropicalextinction. Where naturalists of thananswers suggest themselves: Are Cave enjoythis aspect of thejournal; but increas- thenineteenth century perceived little in the Swallowschanging their usualmigratory inglyI perceiveit to be a valuableresource wayof ornithologicalpatterns in suchdistur- patterns,or havewe simplybecome more fordocumenting the often dramatic plight of bances,twenty-first century birders execute awareof thisspecies, when to expectit, and our avifauna--thedynamic movements of sophisticatedsearches for seabirds in theinte- how to identifyit? Hasthe flightof Cave species,whether in migrationor moresubtle rior,drawing on both history and technology Swallowsbeen overlooked, or is the increase passages,the ever-changing canvas of breed- We livein thetime of theBig Picture. 14 NORTH AMERICAN BIRDS Figure1.Up to four American Pipits ofthe Asian racejaponicus werefoundin the Southern Pacific Coast Region infall 2003. This bird photographed 12October near Imperial Beach, SanDiego County showsthe distinctive features ofthe subspecies, including heavier back streaking, grayer back, bold blackish streaking inthe malar area and underparts, andpinkish legs, all distinctions fromNorth Americantaxa. œhotographsbyLarr•$ansone. That the Americanlandscape will con- ence, whatever our errors or occasional in the East; the influences of Hurricane tinue to be altered is incontestable: human misidentificationsalong the way. Theinfor- Isabel; and the continuing increase in populationswill grow,habitats will be lost. mationcontained in thesereports does not recordsof extralimitalhummingbirds. resourceswill be consumed,and species will lackvalue, whether or notit influencespub- become endangeredand extinct. The lic policy,land-management decisions, or WeatherSynopsis planet'schanging climate, whose Big Picture conservationbiology (as it does,frequently). As an enthusiastof both birds and weather,I we are slowlycoming to understand.will Mostimportant to realize,when we take that readeach regional editor• weather descrip- ensurethat other, perhaps radical changes in extra time to sendthe regionaleditors our tionsand bird-relatedhypotheses with great habuatsthat are forecastwill cometo pass: findings,is thatwe cannotknow today how interest. Not only doesthis information Alpinemeadows become forested, ice sheets the contributions made here--the hard brightenthe regional reports with localfla- melt, sealevels rise, the Evergladesvanish. work of many observersthat collectively vor, it allows all of North America'sbirders To step back from the specificsof the producesa snapshotof North American to glimpsethe conditionsencountered in regionalreports herein, and to imaginethe birdlifeeach season--will prove useful or eachregion and imagine what it mighthave future birdlife o[ the Americas as different importantin the future. The astonishing beenlike to bird there. The compilationof fromtoday as today'sis fromthat of 1604: informationin thesepages is invariablysub- this information over time will lead to a bet- the BigPicture can seem bleak. Afterall, tler thanthe waywardSiberian Accentor in ter understandingof how bird migration, who couldhave imagined two centuriesago Montana or Yellow Wagtail in Alabama extralimitaloccurrences, and weatherphe- that the PassengerPigeon would become (thoughthese are marvelous discoveries). It nomena are linked. extinct,when cloudso[ this speciesonce is insteadthe Big Picturethat canbe inti- Byand large, the Northeast south through movedlike greatstorms across the skies? mated•n the manyand interconnectedpat- the Carolinasexperienced an activeweather We havefew quantified data on thesebirds, terns of bird movement acrossthe continent, patternthis fall, moreso after September. justthe anecdotal astonishment of observers weather-related or otherwise. For the hurricanesaside, that is. Augustand Sep- who [ound them innumerable. Take heart, autumn of 2003, patternsthat suggested temberwere quite wet overmost of theEast then, in the contributionsmade