Quick viewing(Text Mode)

An Experiment in Songbird Management

An Experiment in Songbird Management

Vol.194o•7-] a McAx•:, SongbirdManagement 333

AN EXPERIMENT IN SONGBIRD MANAGEMENT

BY W. L. MCATEE

A PROJECTfor increasingthe numberof to controlnut in an orchard of blight-resistantchestnuts at the Bureau of Plant Industry Experiment Station near Glenn Dale, Maryland, was carried on cooperativelyby that organizationand the U.S. BiologicalSurvey from 1926to 1931. Entomologicaland managementresults have been reportedin the paperslisted in the terminal bibliography,and the more strictlyornithological findings are presentedin this communica- tion. The area involved was about two and one-half acres the first two yearsand three and a half the last four. It waspretty fully occupied by the chestnutorchard and a rosegarden, yet had ample openings. A bath, a martin house, and at the maximum 98 individual bird boxes including five sizeswere installed. Responsewas good and, there being no hole-nestingspecies on the tract before, the threefoldto fourfold increasein birds wasclear gain. The bird pop- ulation was multiplied but the nut weevilswere not perceptiblyre- duced in numbers; their increase,however, may have been checked. Ornithologicalgleanings are here summarizedas 'Nest Analyses' and 'Nesting Results.' NEST ANALYSES On November 18, 1926, E. A. Preble helped me to collect twenty birds' nestsfrom trees in the experimentalchestnut orchard. Ma- terials usedin twelve of these (consideredto be correctlyidentified) are reportedon here. The insectsand spidersusing thesenests as winter quarterswere treated in papersby McAtee (1927b) and Malloch (1927b). Building Materials

Tree Nests Robin.--Three nestsagreed in having weed stalks,dry grass,and mud in their foundationsand fine dry grassfor linings. One had a few twigs and another someleaves in their bases. In nest No. lva few grassseeds in the mud layerhad sprouted,and in connectionwith an embeddedgarlic bulblet with its thread-likeappendage, added fine greenfilaments to the lining. Nest No. 2 held a stratiomyidfly (Odontorayia)and three small bivalves (Pisidiuraabditura), •34 McATEE;Songbird Management [AukL July aquatic forms, undoubtedlygathered with the mud. Nest No. 3 also had a garlic bulblet as in No. 1. .-Twelvenests were madeof the followingmaterials, the frequencyof useof whichis indicatedby thenumbers in parentheses. Foundation:coarse weed stalks (11), leaves(7), paper (7), coarse twigs(5), red-cedarbark (4),grass (3), chestnutbark (1), andlumps of dirt (1). Lining:in eachcase (12) madeexclusively of rootlets. Box Nests On September23, 1926,the contents of all bird boxesand on July 8 andAugust 16, 1927,of thosenot in actualuse by birds,were re- movedto the laboratoryfor study. Materialsused by the different birds(listed in thesame as in Table 1) arehere noted. .--Asa rule the Starlingnests were of slight construction and with little differentiationbetween foundation and lining. In six nestsanalyzed, weed stalks (including Solidago) and grass (including Andropogon)were used in thefoundations of six and five,respectively. Other objectswere straws(up to 11 incheslong), leaves,chestnut spikes,twigs, vines (up to 18 incheslong), and a pod of wild bean (Strophostiles).The 'lining' includedfeathers in four nests,red-cedar barkin two,and leaves in two. Observationsthrough five years showed that most Starling nestsin actual usewere adornedwith one or more freshleaves of yarrow (Achilleamille[olium). House .-Thirty-threecomplete or partial nestswere analyzed. Foundationsincluded (in the numberof nestsindicated): twigs (33), feathers(16), chestnutspikes (13), wool (12), leaves(7), cord (6), and weedstalks (5). Materialsused in fewerinstances were: rootlets, red-cedarbark, cotton, grass, chestnut shell, paper, a largefragment of snailshell, exoskeletons of milleped and sowbug,and a spidercocoon. The twigswere characteristically coarse and includedsome up to eightinches in lengthand a fewthat were branched. Rose twigs with plentifulthorns were frequently employed, and in a few casescallow youngwere raised in suchnests with little or no cushioningto pro- tect them from the spines. The twig basesof nestswere often from four to six inchesdeep. Flecksof wool and cottonwere scattered throughthe twig basesto no conceivablepurpose. The lining of the 33 nestsincluded grass in 19 cases,hair, chieflyhorsehair, in 16, feathers in 13, and rootlets in six. Other items were red-cedarbark, chestnutspikes, weed stalks,and grass. The material'in one nest, loosenedup in the processof' analysis, filled a tWo-gallonbucket. EnglishSparrow.-Five nests studied were bulky and composed chieflyof dried grassand feathers,the latter formingmost of the Vol.194o•7'] a McA'r•, SongbirdManagement 335

lining in each instance. Other substancesused, chiefly in the base, included:red-cedar bark, weed stalks,and rootlets. The nestsap- parently are relined with feathersas excreta accumulate,and there may be severallayers of suchbedding. Bluebird.-In eight nestsgrass predominated both in bases(7) and cups (5). Other foundationmaterial includedweed stalks (4), twigs ($), leaves(2), and feathers(1); and lining, feathers(2). Purple Martin.-The martins scarcelycan be said to make nests, bringing in to their housesa miscellaneouscollection of litter and bric-a-brac. Plant fragmentsincluded straws (up to 16 incheslong) and other grassstems (including Andropogon),weeds (representing the generaRumex, Silene,fragaria, Oenothera,Solanum, and Plant- ago), leaves,twigs (up to nine incheslong and a quarter of an inch thick) includingsome of rosewith thorns,fragments of the wall of cornstalk,a pod of partridgepea (Chamaecrista),and bulbletsof gar- lic. Odds and endswere: bits of oystershelland porcelain,pebbles, lumps of day, and plant labels (one of wood measuring0.5 by 3.5 inches). CrestedFlycatcher.-This bird's housekeepingwas about on a par with that of the martin. Materials rudely piled in a thin nest in- cluded:weed stalks, rootlets, a twigof sassafraswith flowersand green berries,maple samara,onion skin, and snakeslough. It is of interest to notethat a pieceof thislast substance also was incorporated into the only Tufted Titmousenest that wasbuilt in the boxes. (A summary of the useof snake-skinsby birdsmay be foundin Contrib. 11, Baylor UniversityMuseum, 12 pp., 1927,by John K. Strecker.) Food Remains Examinationof nests,particularly those in bird boxes,is a profit- able methodof learningabout the foodof birds,that hasas yet been very little exploited. The resultshere givenprobably are typicalof whatcan be expected.Care is necessary,ascontamination is probable in direct proportionto the ageof the nest. Someintrusive material as that broughtby miceis easilyrecognized, but that introducedby invadingbirds may be more difficultto eliminate. In casesof doubt, recordshave beenrejected as hasalso all evidencefrom boxesknown to have been usedby more than one speciesof bird. For safety's sakeall scavengerforms have been omitted, though possibly some of them were food items. Grateful acknowledgmentis made in connectionwith theserecords for identificationsof: dragonflies(to C. H. Kennedy), (L. L. Buchanan),and Diptera and (J. R. Malloch). 336 McATEE,Songbird Management L[-Auk July

Asterisksfollowing namesin the lists denote insectsof enough economicimportance to be referred to in the list of commonnames approvedby the AmericanAssociation of EconomicEntomologists. Variousspecies besides those so designated,however, are known to be destructive. Tree Nests Robin.--Plant remains:seeds of sassafras,poison ivy, and smooth sumac. remains:spotted cucumber (Diabrotica•2-punctata), (Carabidae),caterpillar, and spider. Catbird.--Plantremains: seeds of mulberry,sassafras, and cultivated cherry. Animal remains: dragonfly,cricket (Orocharissaltator), stink-bug (),ground beetle,leaf-chafer (), locust leaf- miner (Chalepusdorsalis), weevils, caterpillars,ants, yellow jacket (Vespula),and (Agaposternon).

Box Nests Starling.-Plant remains: seedsof mulberry, sassafras,rose, black- berry, cultivatedcherry, and dogwood. Animal remains:earthworm cocoon, centiped, millepeds, grasshop- pers (includingArphia xanthopteraand Melanoplus),crickets (in- cludingGryllus and Nemobius),stink-bugs (Euschistus sp., E. tristig- rnus, Hyrnenarcys nervosa, and Peribalus lirnbolarius, assasin-bug (Sinea),tiger beetle (Cicindela),ground beetles (including Calosorna calidurn,C. sayi,Poecilus sp., P. lucublandus,Percosia obesa, Galerita, Cymindis,Chlaenius sp., C. tomentosus,Cratacanthus dubius, Harpa- lus caliginosus,H. erythropus,H. pennsylvanicus,Triplectrus rusticus, Anisodactylus, Ornophron), (Chauliognathus rnarginatus), click-beetles(Monocrepidius auritus, Hernicrepidius rnernnonius, Melanotus), (Opatrinus notus), dung beetles (Can- thon laevis,Bolbocerosorna farcturn, Geotrupes), leaf-chafers (Diplo- taxis, Phyllophagacrenulata, P. fraterna, P. luctuosa,P. tristis,Ano- rnala, Pachystethuslucicola, Dyscinetustrachypygus, Ligyrus gib- bosus%Euphoria herbacea),leaf beetles (Leptinotarsa•o-lineata% Zygograrnrnasuturalis, triangularis, Chaetocnerna, Chalepus dorsalis*), weevils (Epicaerus irnbricatus*, Brachyrhinus ovatus, Hypera punctata*, Hyperodes,Listronotus, Gyrnnetron tetrurn, Chal- coderrnuscollaris, Tyloderma foveolata, Sphenophorus inaequalis), caterpillarsand chrysalides(), parasitic wasp (Ichneu- moninae),paper wasp (Pollsres),honeybee (Apis rnellifera),ants (in- Vol.tl7-] McATi;E,Songbird Management 337 194o .i cludingLasius), spiders, and snails (includingGastrodonta ligera and Planorbis). .--Animalremains: (including Melanop- lus), crickets,stink-bugs (including Euschistus sp. and E. tristigmus var. pyrrhocerus),Alydus eurinus, ground beetles (including Calathus and Harpalus), leaf-chafers(including undulata), striped blister-beetle(Epicaura vittata*), click beetles(including Monocrep- idius auritus), caterpillars,moths, paper wasp (Pollsres),ants (in- cluding Camponotusand Myrmicinae), and spiders. English Sparrow.--Plantremains: corn, , oats, and wild-grass seeds. Animal remains: earthworm cocoon,grasshoppers (including a locustid),stink-bugs (Pentatomidae, including Peribalus limbolarius, Euschistussp., E. tristigmus,Hymenarcys netrosa, Acrosternum hilare, and Stiretrusanchorago), Orthaea basalis, tree-hopper (Thelia bimac- ulata), leaf-hoppers(Draeculacephala mollipes, Deltocephalus inim- icus,Phlepsius irroratus), tiger beetle (Cicindela),ground beetles (in- cludingCratacanthus dubius, and Triplectrusrusticus), flower beetle (Mordellistena),click-beetles (including Monocrepidiusauritus, M. vespertinus,and Melanotus, both adult and larva), ladybird beetles (H ippodamia• 3-punctata,H. parenthesis,and H. convergens),Isomira sericea,dung-beetles (Aphodius sp., A. distinctus,Psammobius), leaf- chafers (Phyllophagaprobably gracilis,Macrodactylus subspinosus*, Anomala undulata, Pachystethussp., P. lucicola,Ligyrus gibbosus*, Cotinis nitida*, Euphoria sp., E. inda*), leaf beetles (Chrysochus auratus, Chalepus dorsalis*), weevils (including Phyxelis rigidus, Epicaerusimbricatus*, Sitona hispidula*, Hypera punctata*, Phyton- omus,Hyperodes, Balaninus algonquinus and B. sp., Lixus, Baris, Anacentrussp., A. bracata,Tyloderma), bill bugs (Sphenophorussp. and S. destructor), (Nephrotomaincurva, Chrysogaster, Syrphus americanus,Rivellia micans),parasitic wasps (Ophioninae,includ- ing ), ants (includingLasius), and spiders. Bluebird.--Animal remains: ,cricket, ground beetle, dung-beetle(Aphodius), and spider. Purple Martin.--Animal remains:dragonflies (including Tetragon- euria canisand Pachydiplaxlongipennis), earwig (Labia minor), grass- hopper (Melanoplus),stink-bugs (including Euschistus tristigmus vat. pyrrhocerus,Hymenarcys herrosa, semivittata,Nezara hilaris, and Podisus),other bugs (Anasaarmigera, Alydus pilosulus, Acanthocephalaterminalis, Leptoglossus corculus, Cnemodus mayor- flus, Heraeus plebejus,Ligyrocoris, Nabis, Lygus pratensis*, and 338 McATEE,Songbird Management [Aukg July

Pelocoris [emoratus), leaf-hoppers (•lulacizes lateralis, Phlepsius), spittle (Clastoptera),ground beetles (including Poeciluschal- cites,Curtonotus pennsylvanicus, Leiocnemis avida, and •lmara), water beetles (Sphaeridiumscarabaeoides, ), click beetles (in- cluding Limonius, Monocrepidiusbellus, Pheletes nimbatus, Crigmus abruptus, Megapentheslimbalis, and Melanotus), flat-headedwood- borer (Buprestisruffpeg), sap beetles (Pallodes pallidus, Glischrochilus sanguinolentus),Isomira sericea,powder-post beetle (Scobiciabiden- rata), dung-beetles (Onthophagus janus, •lphodius distinctus, •1. fimetarius, •ltaenius cognatus), leaf-chafers (•lnomala undulata, Pachystethusoblivia, Euphoria herbacea, Cotinis nitida*), round- headedwood-borers (Judolia cordi[era,Stenostrophia nitens, Typo- cerussinuatus, Calloides nobilis), leaf-beetles (Paria canella, Chalepus dorsalis*),weevils (Sitonahispidula*, Hypera punctata*, Balaninus), engraverbeetle (Ips grandicollis),caddis-flies, two-winged flies (Chir- onomidae,Michrochrysa, Tabanus, Dolichopodidae, Eristalis, Sphaer- ophoria, Phorocera,and another tachinid), parasiticwasps (Tiphia, Odynerus,Psammocharidae, Sphecidae, Ophioninae, •lmblyteles, Ich- neumoninae,Braconidae), ants (Formica,Camponotus herculeanus*, Lasiusniger*, Myrmica rubra, Ponerinae), (Halictus, •lgaposte- mort, •lpis melli[era), sawfly (Urocerusalbicornis), and spiders (in- cluding Attidae). CrestedFlycatcher.--Plant remains: seeds of mulberry. Animal remains:green stink-bug (•lcrosternum hilare), dungbeetle (Bolbocerosomafarcrum), leaf-chafers (Euphoria sepulchralis,E. herbacea,Pachystethus lucicola), (Photinus),butterfly, and spider. NESTING RESULTS Proportionsof Completeand IncompleteNests Occupancyof the individual bird boxes,with specialreference to the relative numbersof completeand partial nests1926-31, is sum- marized in Table 1. Wrensas a groupare notedfor buildingfalse nests and the House Wren upheldthe reputationof the family in that respectby its con- duct as observedin the Glenn Dale investigations.Not only were well-developednest bases built that werenever further used, but a few coarsetwigs of the type so freely usedby the wren were placed in almostevery box. It is of interestthat the EnglishSparrow built about20 per centof unnecessarynests and the Starlingnearly 25 per cent,the latter bird thuskeeping pace with the wren'in this futility, Vol.194 ø•7] J McAr•.•.,Songbird Management 339

TABLE 1

COMPLETE AND PARTIAL NEsTs

In 46 boxes In 98 boxes Percent- age of partial 1926 1927 1928 1929 1930 1931 Totals nests

Starling Complete nest ..... -- 9 14 36 31 35 125 Partial nest* ...... 1 4 11 12 9 3 40 24.24 House Wren Complete nest ..... 12 21 34 39 29 18 153 Partial nest ...... 9 9 9 8 10 7 52 25.36 English Sparrow Complete nest ..... -- 6 7 5 8 16 42 Partial nest ...... -- 6 1 -- 2 1 10 19.23 Bluebird Complete nest .... 4 5 6 7 4 5 31 Partial nest ...... 3 11 8 9 2 3 36 53.75 Crested Flycatcher.. 1 -- 1 I 1 1 5 -- Flicker ...... -- 1 1 -- __ __ 2 -- ..... -- __ __ 1 -- __ 1 -- Unknown bird ...... -- 2 -- 1 -- __ 3 -- Total boxes with com- plete or partial nests of birds t ...... 26 44 67 82 72 61 352 -- * Or roost. t Includingrecords of well-developedbases but not of a few twigs or a little debris. but it wasa surprisethat the Bluebirdshould far exceedany of these commonbreeders with more than 50 per centof falsestarts. The 'unknown'bird nestsentered in the table were probablythose of native sparrowsexperimenting with bird-boxoccupation but not persistentenough to go throughwith the tests. Sizeof Clutchesand Length of Nesting Season Althougheggs were not countedin all instances,they were enumer- ated in a sufficientnumber of clutches,believed to be complete,to makea summaryof the resultsof interest (seeTable 2). The modal numberof eggsin a clutchwas five in the caseof eachspecies other than the House Wren and for it six. It seemsprobable that the nine recordedfor the Starlingwere a compositeclutch; moreover it came to a 'bad end. Wherere-nestings in thesame box were involved, the number'ofeggs in the first clutch was usually, but not always,larger. Data as to 3'/0 McAxEE,Songbird Management LI'Auk July tandemclutches are presentedin Table 3. A triple nestingby Eng- lish Sparrowsviolated the rule by running four, five, five.

TABLE 2 FREQUENCYOF CLUTCHSIZES

Number of eggs Species Total 2 3 4 5 6 7 8 9 clutches

Starling Number ..... 6 10 27 42 15 -- -- 1 101 Per cent ...... 5.94 9.9 26.73 41.58 14.45 0.99 House Wren Number ..... -- 4 16 28 30 20 -- -- 98 Per cent ...... 4.08 16.32 28.57 30.61 20.41 English Sparrow Number ..... 5 3 9 10 2 ------29 Percent ...... 17.24 10.34 31.03 34.48 6.90 Bluebird Number ..... 2 5 6 7 .... 20 Per cent ...... 10.0 25.0 30.0 35.0

TABLE 3 Numberof First First Average Average clutches larger smaller offirst of second Starling ...... 15 10 1 5.13 4.00 House Wren ...... 7 5 -- 6.14 4.57 English Sparrow ...... 5 2 1 4.6 4.00 Bluebird ...... 2 2 -- 4.5 3.00

Clutches of a few other speciesnumbered: Flicker, seven, five; CrestedFlycatcher, four, five, five; and Tufted Titmouse,three. Dates for the earliest eggsand latest young in nestsmay be tabu- lated as follows: Earliest eggs Latest young Starling ...... April 23 July 8 House Wren ...... May 10 August 8 English Sparrow ...... May 2 July 24 Bluebird ...... April 30 July 7

For the threeother species,corresponding data basedon only a few recordsare: Flicker, July 8, July 91; CrestedFlycatcher, June 9, July 7; and Tufted Titmouse, June 15, July 10. The peakof thenesting season, that is, the visiting day upon which most housescontained eggs or young, was as follows: 1998, May 99; 1999,June 15; 1950,May 91; and 1951,June $. Vol.•94o 57] J MeArEE,Songbird Management 3'tl

Serial Nestings If incompletenests were considered,the recordof impositionof one on anotherof a differentspecies would be prolix and confusing. To make the confusionworse, birds incorporatedin their neststhose of mice and the latter animalsand bumblebeesappropriated bird nests. Even building upon an occupiednest possiblycontaining eggs was not taboo,and in a few casesthis activitywent on to completionand eggswere buried by the intruding nest. Examples:wren on Blue- bird nestwith one egg; wren on Bluebird nest and two eggs;English Sparrowon wren nest containingone young wren-a brood of had fledgedso this youngsterwas probably dead before the sparrows began building. Non-conflictingre-nestings producing 'broods' in singleboxes dur- ing the sameyear are recordedin Table 4.

TABLE 4 MULTIPLE NESTINGS IN SINGLE BoxEs IN THE SAME YEAR

1926 1927 1928 1929 1930 1931

Two ' broods' Starling ...... -- 2 -- 8 5 8 House Wren ...... -- 2 3 2 3 1 English Sparrow...... -- I -- 1 1 4 Bluebird ...... 1 -- 1 1 -- 1 Three 'broods' English Sparrow...... -- .... 1 Wren following Bluebird ...... -- 1 2 I -- -- Wren following sparrow ...... -- -- 1 1 -- 1 Wren, sparrow, wren ...... -- -- 1 ------Bluebird following sparrow ...... -- 1 .... Flicker following Starling ...... -- -- 1 ------

Apparentlythe Starlingsdid not graspthe idea firmly at first but later werestrong for it. The instancesof speciesfollowing others in various orders are of interest. The 'Flicker following Starling' case showsthat if there was any battle it was not lost by the Flicker. In fact, in the box involved in the 1928 record, had made a nestand laid four eggswhich, lying unchangedfrom May 22 to June 9, were removed. Whether Flickers had anything to do with this failure to incubateis unknown,but on July 7 there were five young Flickers in the house, of which three were raised. In 1927, seven Flicker eggswere laid in a box from which a dead adult Starlinghad been removed. This bird had a hole in its head and a female Flicker 342 McAxEE,Songbird Ma*mgement [AukL July similarly woundedwas found in 1928 in a box in which the base of a Starlingnest was presentboth beforeand after the Flickeftsdemise but in which no eggswere laid. One oœthe strongestcomplaints about the Starlingis that charging excessivecompetition with native birds for nestingsites and victimi- zationof the Flickeris especiallydeplored. Sofar asthe evidenceof conflictdeveloped in this studyis concerned,however, the Flicker seemedto come out slightly ahead. Returning to the subjectof re-nestings,the usual rule was for a houseto be occupiedby the samespecies year after year. There were some deviationsand in the period 1928-31, out of 86 occupied boxes,16 were usedby two speciesand three by three. The birds in the last serieswere in eachcase, Wren, EnglishSparrow, and Bluebird. Broodsproduced in bird housesannually and per acre,reckoning as a 'brood' anythingfrom one egg to a nestfulof fledglings,are recordedin the followingTable (5).

TABLE 5 Year Total'broods' 'Broods' per acre In 46 boxes (on 2.5 acres) 1926 ...... 17 7.6 1927 ...... 39 15.6 In 98 boxes (on 3.5 acres) 1928 ...... 64 18.3 1929 ...... 93 26.6 1930 ...... 69 19.7 1931 ...... 72 20.5

These figuresdo not includetree-nesting species nor do they indi- cate pairs per acre. Authentic figures in either of those respects probably could have been obtained only by intensivebanding and trapping. The first year evidentlywas a get-acquaintedperiod; the birds required time to learn about the boxes. Responsemeasured by grossproduction of 'broods'increased for four years (1926-29) then dropped30 per cent in 1930. No correlationseems probable except with the drought of that year. A weather-reportingstation is on the ground where the work was done and the recordsas to temperatureand precipitationfor the monthsApril to August,1926- 31, inclusive,have been carefully scanned. The only considerablo departurefrom normal is in precipitationfor 1930,a year which is on recordas the driestin Maryland since1870. The droughtbegan in December1929 and endedin February1931; for the calendaryear 1930,precipitation was 29.58 inches, which is 21.51inches, or 58 per Vol..•7] McAT•,Songbird Management 3't3 cent, belownormal. Accordingto the local station,only 7.47 inches of rain fell in the monthsof April to August1930, inclusive. Ap- parentlythis dry weatherhad an adverseeffect upon collectivebird propagationthat wore off only slowlythe next year,which was2.25 inchesdeficient in precipitation. Nesting Success More definitefigures as to the productionof eggsand youngby the four more commonspecies of birds usingthe single-apartment housesare presentedin Table 6.

TABLE 6

Known nestingsuccess Species Total eggs Probab• total Year in a• Eggs Young Efficiency youngproduced boxes laid fledged rate in a• boxes

Starling 1928 ...... 50 50 36 72.0 36 1929 ...... 148 148 122 82.5 122 1930 ...... 128 128 115 89.7 115 1931 ...... 146 146 137 93.7 137

Totals ...... 472 472 410 av. 84.5 410

House Wren 1928 ...... 140 140 121 86.4 121 1929 ...... 193 182 152 83.5 161.1 1930 ...... 113 99 91 91.9 103.8 ? 1931...... 71 48 35 72.9 51.7

Totals ...... 517 469 399 av. 83.7 437.6

English Sparrow 1928 ...... 23 23 17 73.9 17 1929 ...... 19 16 11 68.7 13 1930 ...... 16 16 12 75.0 12 1931 ...... 69 59 57 96.6 66.6

Totals ...... 127 114 97 av. 78.5 108.6

Blueb•d 1928 ...... 21 21 17 80.9 17 1929 ...... 25 25 21 84.0 21 1930 ...... 13 13 13 I00.0 13 1931 ...... 15 15 15 100.0 15

Totals ...... 74 74 66 av. 91.2 66 3,• MCATEE,Songbird Manage,tent [AukL July

Of interestin Table 6 is the showingof highestefficiency by a nativebird,--the Bluebird. The numbersof eggsand younginvolved are perhapsnot largeenough to haveas good statistical value as those for the Starlingand the HouseWren. They are comparablewith thosefor the EnglishSparrow, however, and show that thissupposedly dominantspecies is very poor in nestingefficiency in comparisonto the Bluebird,--78.5:91.2%. The averageefficiency rates for the Star- ling and wren are for all practicalpurposes the same. Similarrecords for threeunusual breeders for the sameperiod are given in Table 7. The efficiencyrates in this case,while of interest, are not statisticallysignificant.

TABLE 7 Species Broods Eggs Young E•ciency Crested Flycatcher ...... 3 14 8 57.1 Flicker ...... i 7 5 71.4 Tufted Titmouse ...... 1 3 3 i00.0

Nesting Losses The birdsdiscussed in thispaper belong to the favoredhole-nesting associationwhirls, on the average,suffers fewer nesting lossesthan other groups (upland ground-nesters,43%; bush. and tree-nesters, 52%; and hole-nesters,73%; see Kalmbach,E. R., Trans. Fourth No. Amer. Wildlife Conference,1939, p. 601), yet from the human point of view the wastagein eggsand youngseems unnecessarily high. In a studysuch as this carriedon by periodicinspections (often at longer than desirableintervals), the causesof lossescould hardly be determined. In someinstances eggs disappeared from a nest one at a time, in othersthey vanishedas entire clutches. On the other hand, eggsre- mainedin severalnests over the winter,--aperiod of more than eight months. Usually there was no clue to the agent responsiblefor lossesand exceptin a few casesthe eggswere cleanly removed. Those found brokenin the nestsappeared to have beendestroyed by family inefficiencyrather than by interferenceby intruders. Squirrel gnaw- ing was noted about the entrancesof a few nest boxesbut no other evidencewas obtainedof depredationsby theseanimals. In a box occupiedby wrens,a set of five eggsobserved on July 7 remained without changeuntil 'August18. On that date, examinationre- vealedparts of a snakeslough in the house. Had a snakecaptured one or both of the parents? If so, why did it not eat the eggs? Snakesheddings are usedby wrensas nestmaterial so their presence Vol.t94o•7] J McAxEE,Songbird Management 345 in this bird housemay be explainedin that way. The casewas a mysteryas were most of thoseinvolving lossesof eggsor young. In someinstances one or moreeggs disappeared but the remainder were hatchedand the nestlingsfledged. If the egg removerwas animate,why did it not persist?Perhaps something ended its career. Possiblysome bird neighborhad sufficientmotive for a certaindegree of trespass,then lost the urge. Who knows?Who can know? Interferenceon our part changedthe courseof one nestingloss. On May 22, we found two Bluebirdeggs on the groundbelow a box. We put them in the house,on May 30 found three eggsin it and on June 13, three young that were successfullyfledged June 26. Tables 8 and 9 showrecorded losses of eggsand young. Roughly, they seemto keep pace with production,the high number in each seriesoccurring in 1929when reproductive effort was at its maximum for the period of the investigation. At this point it may be enlighteningto mentionbriefly the findings of this studyas to the bird's-nestfly, Protocalliphora. Blood-sucking larvae of this genusmay well have been responsiblefor the death of a goodmany of the nestlingsfound dead in the boxes,but that they are not fatal invariablyor evenin a high percentageof casesis shown by the abundanceof puparia (their resting stage) in nests from which broodshad fledgedwithout loss. As an outstandingcase, 340 specimens(in all stages)of the flieswere sorted out of the contentsof the martin housein 1927 when no dead youngwere found. This is

TABLE 8 ABANDONED EGGS* [Number of nests involved and (in parentheses)total number of young[

Y•ar Species Totals 1926 1927 1928 1929 1930 1931

Starling...... • -- -- 6(7) 4(5) -- 10(12) House Wren ...... o 1(2) 6(10) 6(13) 4(7) 1(2) !8(34) English Sparrow...... •' 2(2) 1(1) -- -- 1(1) 4(4) Bluebird...... • -- 1(1) 3(4) -- -- 4(5) CrestedFlycatcher .... •. -- -- 1(1) -- 1(1) 2(2) Flicker. TuftedTitmouse .....

Totals...... 3(4) 8(12) 16(25) 8(12) 3(4) 38(57) * Including alsoinfertile, addled, and broken eggsbut not thosewhich disappeared from the nests. 3'}6 McATEE,Songbird Management L[ AukJuly

TABLE 9

DEAD YOUNO IN NEST BOXES

[Number of nestsinvolved and (in parentheses)total number of young]

Y•a• Species Totals 1926 1927 1928 1929 1930 1931

Starling...... -- 3(3) 1(4) 8(13) 6(12) 3(7) 21(39) HouseWren ...... 3(4) 1(1) 7(10) 3(8) -- 2(10)' 16(33) EnglishSparrow ...... -- 1(1) -- 1(4) 2(2) -- 4(7) Bluebird...... -- -- 1(1) -- 1(2) -- 2(3) CrestedFlycatcher .... 1(3) ..... 1(3) Flicker...... -- -- 1(2) ------1(2) Tufted Titmouse ...... --

Totals...... 4(7) 5(5) 10(17) 12(25) 9(16) 5(17) 45(87) an averageinfestation of nearly 90 of the bloodsuckersto a brood of nestlings,yet all of the latter survived. Ornithologistsdoubtless will be pleasedto learn that the Protocalliphorathemselves suffer severelyfrom the attacksof parasitesand predators,50-65 per cent mortality being disclosedin this study. It was difficult to resist the condusion that desertion was the cause of someof the lossesof nestlings,as, for example,those of two broods of three eachof Starlingson June 26, 1931. Starlingswere at that time near the end of their nestingseason and the pull of the flockmay have overpoweredthe urge to care for their young. The fledging of part of the brood may have providedthe stimulusto depart; in one casea singlenestling and in the other, two, may have taken to wing before their nest mates. It maywell be remarked,however, that in the Districtof Columbia regionthe cyde of Starlingactivities appears very confused.Pairs frequenttheir nestingsites and malessing there, if not continuously, at least at intervals,throughout the year. Again, flockingin some degreeis a practicallyperennial phenomenon, remnants of the bands that spendthe winter nightsin the city persistingpast the time when settledpairs are nestingand almostup to the time whennew flocksof youngbirds are formed. Hence if occasionalStarling parents desert a belatedbrood, the actionmay be attributableto confusionin instinctivedrives. To paraphrasean entomologicalcouplet, the Starling,if it could,might well say: Vol.194o•7' aI McAIEE,Songbird Management 3't7

My urgesstrong, now here, now there, Oppressmy bosomwith despair.

History of the Purple Martin Colony Mostof the discussionand tabulationhas ignored the martincolony not becauseit lackedinterest but becauseits comparativelyelevated abode could not be inspectedlike the readily accessiblehouses of individual bird families. The martins as alwayswere a musical, active,and colorfulcomponent of the bird population,and we were fortunatein gettinga colonythe firstyear and in retainingit through the investigation. Like most of the other birds, the martins had their bestyear in 1929. Intrusioninto their quarters(with no inter- ferencefrom us) tendedto increasethough it never becameserious. Occupancyof the martin house and known lossesof martins are shownin the following tabulation.

Pairs* of Intrudon by other species Year Martins Losses (pairs) 1926...... 3 4 young 1927...... 4 2 eggs English Sparrow, 1 1928 ...... 7 -- English Sparrow, 1 1929 ...... 9 -- English Sparrow,2 1930 ...... 7 -- English Sparrow, 1 1931 ...... 7 -- English Sparrow, 2; Starling, 1; Bluebird, 1 (in support). * The househad 16 apartments.

SUMMARY A bird-attractionproject carried on for six yearsin PrinceGeorges County,Maryland, had for its primary objectiveincreasing bird ene- mies of chestnut weevils. A threefold to fourfold increase in the bird populationwas easily attained but the nut weevilswere not perceptibly reducedin numbers;their increase,however, may have been checked. Entomologicaland managementresults have been publishedin eight papersthat are cited. This communicationis devotedto the more strictly ornithological findings, including analysesof nest-building materials and of food remains found in the nests; and tabulations of the proportionsof completeand incompletenests, size of clutches and lengthof laying seasons,serial nestings in singleboxes, nesting success,and nestinglosses. The historyof a Purple Martin colony also is briefly sketched. 3z}8 MeAdE,Songbird Management L[' JulyAuk

BIBLIOGRAPHY MALLOCH,J. R. 1927a.Descriptions of a new genusand three new speciesof Diptera. Proc.Ent. Soc. Washington,29(4): 90-93, 1 fig. bred from nests in boxes. 1927b.Descriptions and figuresof the puparia of Minettia ordinariaand Caliope fiaviceps(Diptera). Proc. Ent. Soc.Washington, 29 (8): 184, 2 figs. Insects bred from nests in trees.

McATEE, W. L. 1927a. Notes on insect inhabitants of bird houses. Proc. Ent. Soc. Washington, 29 (4): 87-90. Insectsrecovered or bred from the nestsof four speciesof birds. 1927b. Bird nestsas insectand arachnidhibernacula. Proc.Ent. $oc.Washington, 29 (8): 180-184. Organismsidentified from nestscollected in trees. 1929a. Further notes on insect inhabitants of bird houses. Proc. Ent. Soc. Wash- ington, 31 (6): 105-111. Fuller noteslike thoseof 1927apaper on insectsfrom nestsof six species of birds. 1929b.Paper wasps(Polistes) as pestsin bird houses. Proc. Ent. $oc. Washing- ton, 31 (7): 136. Noteson frequencyof occurrenceand methodsof control. 1931. Paperwasps (Polistes) in bird houses.Proc. Ent. $oc.Washington, 33 (7): 186. Report on four-years'experience with the wasps;infestations ran from 27.5 to 45.9 per cent; from one to sevenremovals were required to dis- couragethe insects. 1940. A venture in songbirdmanagement. Journ. Wildlife Management,4 (1): 85-89, 6 tables. Descriptionof project; resultsin 'broods'per year and per acre; occu- pancy of bird boxesaccording to dimensions,height from ground, and insolation; notes on intruders. U.S. BiologicalSurvey Washington,D.C.

Top View