Nesting Habits of the Spotted Sandpiper 445

Vol.1937' 541J MOUSLEY,Nesting Habits of the Spotted Sandpiper 445

NESTING HABITS OF THE SPOTTED SANDPIPER •

BY HENRY MOUSLEY

Plates 27, 28 IT certainlycame as a greatsurprise to find that out of over eightyspecies of sandpipersand ploverstreated by Bent in his 'Life Historiesof North AmericanShore Birds, Order Limicolae' (Bull. U.S. Nat. Mus., no. 146, pt. 2, pp. 78-97, 1929), the SpottedSandpiper (Actitis macularia) held the lowestincubation period, namely fifteen days,no other specieshaving less than seventeendays, and only two I think at that, all the othersranging from twenty-oneto twenty-eightdays. In a paperon the 'Diving Habit and CommunitySpirit' of this sandpiperpublished in 1920 (CanadianField- Naturalist, vol. 34, pp. 96-97,1920),I drew attention to the little we really knowof the very intimatehome life and traits of eventhe commonestbirds, as only just lately had the incubationperiod of the CommonSandpiper (Tringa hypoleucos)of Europe (a first cousinto our Spotted)been ascer- tained to be twenty-one days. It was only in 1935, that the opportunity cameto me of goinginto this matter with regardto our SpottedSandpiper, for in that year I wasfortunate enough to find two nestsin the making,and to note the date of the first egglaid in eachcase, besides obtaining pictures of the hatchingof the chicks,their hiding,and the parent broodingthem. Both thesenests were very carefullywatched, and in eachcase the young hatchedout on the twenty-first day from the laying of the last egg. This past year (1936), I had hopedto find thesebirds back on their old ground and to corroboratemy recordsstill further. Only one nest, however,was locatedon June 14 (twelve feet from the site of last-year'snest), but unfortunately it containedfour eggs. From the actionsof the parent as it flushedfrom the eggs(I shallrefer to this later), I think it had beenincu- batinga few days. Theseeggs hatched out on June30, so evenin this case I had watchedthe incubatingbird for sixteendays, and feel sureI could safelyadd anotherfour or five days, as the parent when flushingresorted to the so-called'injury-feigning' trick, as seldomdone unlessincubation has beenin progressa few days; as a rule the bird merelycontents itself with quickly runningoff the nest, without any demonstration,if the set of eggsis incomplete,or quite fresh. When flushing,not only the smallness of the parent,but its behavior,put into my mind two thoughts:(l) Was it the male that wasincubating? and (2) Why not pay especialattention to Dr. Friedmann'stheory regarding this so-called'injury-feigning' trick? With thesetwo thoughtsin mind, I paid frequentvisits to the nest, in all about a dozenon differentdays beforethe hatchingof the eggs. The nest

Read before the American Ornithologists' Union, Fittsburgh, Fa., October 22, 1936. 446 Mo•s•, NestingHabits of the Spotted Sandpiper [Auktoct. wasnearly at the top of a little embankmentalongside a railway track, and it was the invariablecustom of the incubatingbird wheneverI appeared abovethe nest,to run downthe bank and alonga dry ditch at its foot, sometimesdisplaying and squealing(if I attemptedto follow);at others,merely contentingitself with runningalong for somelittle distance,or evenat times standingstill, beforetaking flight. On every occasionit was the samesmall bird with lightly spottedbreast, and at the time I made up my mind to collectit at the end of the study and proveits sex. Fortunately,this was not necessaryas will be seenlater. I never oncesaw a secondbird at the nest,but on one occasiona larger and more heavily spottedone was noted somehundred yards or soaway. On the day of the hatching,however, both birdscame to meet me as I approachedthe nest. I couldsee at a glancethe appreciabledifference in size and heavier markingson the breast of the femalecompared to the male,the smallerand lighter-markedbird I had been watching,and the one that now made all the fussof wing demonstration, sometimescurling itself, as it were,into a little ball as it ran along,remind- ing me very muchof a little hedgehog,whilst the femalemerely ran rapidly aboutin all directions. Therewere no misgivingson my part that the male had done most, if not all of the incubating,as has been proved by Miss TheodoraNelson (Bird-banding,vol. 1, pp. 1-13, pls. 1-6, 1930), and by othersagain in the easeof the male Least Sandpiper(Pisobia minutilla). The younghad left the nest and were in hiding not far off, but I failed to find them, so decidedto give up the searchfor the presentand return againlater, in the hopethat by then the parentswould eventually have led them to more open groundacross the railway tracks (as was the easethe previousyear), where sometimber screensused in the winter to prevent snowdriftson the railway are stackedup at intervals,thus formingexcellent vantagepoints for the parentsto watch the youngand give warningwhen- everdanger threatened. I did not return for somehours, but whenI did, sureenough, the young had beenenticed away fromthe nestto the old feed- ing groundof last year, with a parentkeeping guard perched on oneof the stacks. As I drew nearer, I could see that this bird was the male, who was soonjoined by his partnerwhen he alightedon the groundand ran to meet me. The youngwere not visible,and solong as I remainedstationary, the parents did not display any great emotion,but immediately I began to move about they becamevery excited,especially the male, running all aroundand about me in every direction,thus giving me another excellent opportunityof comparingtheir sizeand markingsat closequarters and on openground, and eliminatingthe necessityof collectingthem. The broken- wingtrick wasnot resortedto by eitherbird, exceptby the male (slightly) on oneor two occasions,when I madeas if to followit; but both birdsmerely contentedthemselves by runningabout very excitedlyin all directions,the

Vol.1937 54]J MOUSLE¾,Nesting Habits of the Spotted Sandpiper 447

male always in the forefront quite close,the female behind him and well away from me. I managedto take a few snapshotsof them, a somewhat difficultand unsatisfactorybusiness with a plate camera. After a time, and failingto find the young,I sat down,when the malereturned to his lookout on oneof the stacks,and the femalemust havequietly taken herselfoff, as I neversaw her again. Resumingmy searchafter a time for the young,I musthave come very neartheir hidingplace in a largebed of tall goldenrods, whichI had not thoughtof lookingin beforefor, without any warning,the male suddenlybecame very excited,flying all aroundme and trying to perchon every obstaclethat camein its way. This remindedme vividly of my experienceat Harley, on July 19, 1915,with an excitedparent with youngunder similar conditions, which finally ended,up by perchingon a cat-tailhead (Auk, vol. 33, p. 66, 1916). When I resumedmy searchnear the goldenrods,the male becamemore and moreexcited, in fact, demented is the only wordfor it, flyingnot only aroundand aboutme, but all overthe area in wide circles,eventually landing on the top of a goldenrodplant whereit becamenormal again, remaining long enoughfor me to take two snapshotsof it in that position. This exhibitionwas so noveland exciting that I decidedto seeif it wouldbe repeatedon a subsequentvisit. So a few dayslater I againvisited the spot,when the youngwould have grown somewhat, and be easierno doubtto find. On arrival, the malewas again on his vantageground, the stackof screens,and by hiding,I at last sawone young comeout into the open(away, however, from the goldenrods);but before I couldreach it the parenthad giventhe warningnote and it had vanished, neverto be seenagain. It wasevident that the youngwere scattered about, as on againapproaching the belt of goldenrodsthe male becameeven more dementedthan on my previousvisit, flying excitedlyabout in all directions as if not knowingwhat to do, sometimestrying to perchin trees,at others on goldenrods,and yet againrunning rapidly over the groundin all directions,without displaying. This latter phase,i.e., not displaying,gave me the ideaof seeingwhat it woulddo if I followedits movementsslowly. So long as I did so, it merelykept runningin front of me, but immediatelyI doubledmy pace,in fact ran, thus gainingon it rapidly,it resortedto the so-called'injury-feigning' trick, rufflingup its feathersuntil it lookedlike a little ball rollingalong, as already described, and sometimes squealing loudly. After thesedisplays had lasted a few moments,the bird becamenormal again,running along the groundfor a shortdistance before rising and flying back to its lookoutpost on the stacks. As alreadymentioned, it is not easy to obtain snapshotsin focuswith a plate camera,irrespective of beingon the spot at the right moment,but I was certainlyfortunate in obtaining abouthalf a dozensomewhat unique pictures of this sandpiperperched in trees and on goldenrodplants, more especiallythe latter. Altogether, 448 MovsL•%Nesting Habits of the Spotted Sandpiper LOc•.[Auk during the three hoursof this and my previousvisit, I must have seenthis bird perchedin theseun-sandpiper-like positions at least two dozentimes. The femalenever put in an appearance,and this wasthe easein the previous year; only one parent was present,and I feel sureit was the male from this year's experience. The male when perchedon the stacksgave vent to the sharp alarm notes weet,weet, almost continuously,interspersed very oc- casionallywith pip, pip, pip, noteswhich I cannotremember having heard at any other time. Before summingup, let us for a moment considerthe literature on this so-called'injury-feigning' subject. First of all, there is Dr. Friedmann's notable work, 'The Instinctive Emotional Life of Birds' (Psyehoanalytie ReGexv,vol. 21, 1934) reviewedin the January issueof 'The Auk' for 1935, in which the author considersthe so-called'broken-wing ruse' of many birds to draw an intruder away from the nest or young, as rather the result of conflictbetween the emotionof fear, oeeasionedby the approachof an ap- parent enemy, and the reproductiveemotion, which makes the bird loath to leave the nest. The conflict of emotionsproduces muscular inhibition or inability to fly, until the fear emotion gains control, as the bird gets farther and farther from the nest. This opinion I find has already been held by Dr. Douglas Dewar who, in his 'Birds at the Nest' (London, 271 pp., 1928) devotes a whole chapter (pp. 167-194) to the 'broken-wing trick.' On page168 he says:"For yearshave I urgedthat it is a mistaketo say that the parentbird pretendsto be wounded. The movementsin ques- tion are the result of mental disturbance,caused by the clashof conflicting instincts--the parental instinet opposingitself to the instinetof self-preser- vation. The resultof this clashof instinctsis that the bird losestemporarily its mental balanceand is unable properlyto control its movements." As long ago as 1847, Dewar goeson to say, JonathanCouch wrote ('Illustra- tionsof Instinet,' p. 243): "It may be questioned,whether the lamenessand fluttering are not so much the paralysingaffections of fear as of cunning," and more recently Eliot Howard as the result of prolongedstudy of the habits of British warblershas assertedthat birds do not deliberatelyfeign injury. Of coursethere are others who hold this 'broken-wingtrick' as instinctive, of which Dewar mentions several whilst giving their reasons supportingtheir contentions. More recently in this category, I might mention the name of the late Harry S. Swarth and others,who have ex- pressedtheir viewsin letters to the Editor in recent numbersof 'The Auk.' After givingthe namesof thosewho do not apparentlysupport his views, Dewar goeson to deal with the viewsand experiencesof thosewho do so, under the followingeight very pertinent headings,which I take the liberty of enumerating: (1) Birds have neither the requisiteknowledge nor the intelligenceto Vol.1937 54]J Mous•.r•Y,Nesting Habits of the Spotted Sandpiper 449 enablethem to practisesuch a ruse. The performers,in orderconsciously to deceive,must know how a bird having a woundedwing behaves. It has no meansof acquiringthis knowledge. (2) If birds when performingthese antics are deliberatelyfeigning injury in orderto enticeintruders from their young,it is mostsurprising that somany specieshave hit uponthis ingeniousdevice, birds belonging to very variedfamilies and living in all partsof the world. (3) Birds often flutter about, as though injured, in circumstancesin whichsuch behavior cannot assist the youngin any way, indeedoccasion- ally, whenit betraystheir presence. (4) If a bird knowinglysimulated injury in order to draw an observer from its youngor eggs,we shouldexpect it to be carefulto keepin view of the intruderwhile so performing, but this doesnot alwayshappen. (5) If birdsfeign injury in orderto enticean intruder from their young, or if the behaviorbe instinctive,we shouldexpect the sameparent to perform the trick with the samevehemence at all timeswhen the youngare unableto moveas quicklyas the parent. This doesnot appearto be the case;at all events,the behavioris not alwaysequally vehementin any given species. (6) If birds feign injury to entice an intruder from their nest, we should expectboth parentsto take part in the game,but this doesnot always happen. Sometimesthe femalewill performthese antics while the male showsfight; at othersthe male appearsto be surprisedat the behaviorof its mate. (7) Eliot Howard records('British Warblers') that warblerssometimes, under the influenceof sexualexcitement, behave as though they were injured. (8) Many birds,when their youngare threatened,perform antics which do not make the bird appearto be feigninginjury. Let us now considerthe points raised in the presentpaper, as follows: (1) that with moreintensive study on the part of otherornithologists, I feel surethat the incubationperiod of the SpottedSandpiper will be foundto be nearer twenty or twenty-onedays rather than fifteen; (2) also, that with more intensive study it will be found that the male more often than is generallysupposed, takes entire chargeof the incubationof the eggs;(3) that the evidenceproduced with regard to the so-calledinjury-feigning trick seemsmore in favor of its being consideredthe result of the clashof conflictingemotions rather than the result of instinct or intelligence. In supportof the former, what better evidencecould be found than the behaviorof the bird on July 6, the day on whichI spentthree hours watching it? As alreadystated, the conflictingemotion of fear at my presencecoupled with the emotionof parental anxietyfor the safety of the youngliterally 450 MousLr¾,Nesting Habits of the Spotted Sandpiper rAuktOc'•. drove the bird crazy, in fact, demented;and its normal equilibriumwas onlyrestored upon its comingto resteither in the treesor on the goldenrod plants. This behaviorseems to fit in beautifullywith what Dewar says: "The resultof this clashof instinctsis that the bird losestemporarily its mentalbalance and is unableproperly to controlits movements." Revert- ing to its behaviorat the nest, this alwaysseemed of a very stereotyped order,for directlyI appearedabove the nestit wouldalways run downthe slopeinto the drain at its foot, run alongthis, sometimesdisplaying, at othersmerely runningfor a short distance,and then taking wing. The broken-wingtrick was only resortedto if I attemptedto follow rapidly (to try and get a snapshot)as wasthe easeon July 6, as alreadydescribed. May we not attribute this behavior on both occasionsto the emotion of self-preservationat my very near approachasserting itself as strongly as the parental emotion,eausing for the moment that muscularinhibition describedby Dr. Friedmann,which prevents the bird fromrising and flying? Certainly, the flight never took place until the bird had come out of its contortions,and had run along a little, and so regainedits normal equi- librium. In conclusion,may not many of the varied anticsdisplayed by birdsat courtshipand other times,be the result rather of involuntarymovements causedby greatexcitement at a time whenthey are in a very nervousstate, rather than the result of instinet or intelligence? Sincethis paperwas written, my attentionhas been drawn to an article 'Injury-feigningin Birds' by the Rev. F. C. R. Jourdain, publishedin 'The Oologists'Record' for June, 1936, pp. 25-37, in which the author statesthat the main objectof hispaper is to showhow far thishabit is prev- alent amongPalaearetie birds, rather than to discussthe meaning and origin of actionsin beingswhose mentality is utterly differentfrom our own. However,while Jourdainadmits that the theory that the bird is the victim of contraryemotions explains most eases, he thinks that it doesnot accountfor all; yet he statesthat the action"is not the result of a thought out plan to makethe looker-onbelieve that the bird hasbeen injured." PosTscaIrr.--Foflowingthe aboveaccount I have had the goodfortune this summer(1937) of verifyingmy suppositionsof last year. The birds cameback and nestedagain in the very identicalspot in the groundas last year; the first egg was depositedon May 25, the last on May 28. After the layingof the eggs,the femalewas never seen again at the nest,not even at the hatchingof the young(as was the easelast year), at whichI was fortunate enoughto be presenton June 17. The incubationperiod was thus twenty daysas againsttwenty-one of last year. The incubatingbird behavedexactly as lastyear, and againI felt sureit wasthe male. Arriving at the nestearly on the morningof June 17, I found two of the youngdried Tu•, Au•, Vo•. 54

SPOTTED SANDPIPER Bl•OODING

NEWLY HATCHED SPOTTED SANDPIPER HIDING Vol.1937 54]J MOUSLEY,Nesting Habits of the Spotted Sandpiper 451 out, the remainingtwo in the wet stageonly partially dried out. On my return sometwo hourslater, oneyoung only remainedin the nest. Two days later, from the actionsof the parent, all four werediscovered with somedifficulty sixty yardsfrom the nest. The parenthad led them acrossone track of railsbut not to the sameground as last year. At a later visit the sameday, the parent had led them still farther away, until they were now 190 yards from the nest, and it lookedas if further delay might loseme the opportunityof this time verifyingthe sexof the parent. Much as I hatedit, I steeledmy heart and collectedthe bird from the top of a box freight-car,its lookoutpost on this occasion,for there were no stacksof timber on this sideof the tracksas there were last year. As I had surmised both last, and againthis year, the incubatingparent turned out to be the male. It shouldnow proveinteresting as well 'asdesirable, to get at the respec- tive r•les playedby the sexesin the homelife of thisspecies. Do the females, as in the easeof the phalaropes,press their suitson the malesat courtship times, or otherwise? Unfortunately, sight identificationsin this matter have so far provedentirely fallacious,and muchas we may dislikeit, the matter can only be definitelysettled by the judiciouscollecting of a number of the displayingor aggressivebirds at courtshiptimes. ½073Tupper Street Montreal, Canada