Predator Density Influences Nest Attendance of Yellow‐Headed Blackbirds Xanthocephalus Xanthocephalus Colby Behrens Iowa State University

Natural Resource Ecology and Management Natural Resource Ecology and Management Publications

1-12-2019 Predator density influences nest attendance of Yellow‐headed Blackbirds Xanthocephalus xanthocephalus Colby Behrens Iowa State University

Zachary J. Ruff Iowa State University

Tyler M. Harms Iowa State University, [email protected]

Stephen J. Dinsmore Iowa State University, [email protected]

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This Article is brought to you for free and open access by the Natural Resource Ecology and Management at Iowa State University Digital Repository. It has been accepted for inclusion in Natural Resource Ecology and Management Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Predator density influences nest attendance of Yellow‐headed Blackbirds Xanthocephalus xanthocephalus

Abstract Nest attendance behaviour in birds is a function of the careful balance between the risk of nest predation and the needs of the parents and nestlings. This attendance must be carefully regulated, as increased parental activity at the nest increases nest predation risk. We tested the long-standing hypothesis that nest predation risk influences parental behavior by evaluating the influence of local Marsh Wren Cistothorus palustris density on the off-bout frequency of Yellow-headed Blackbirds Xanthocephalus xanthocephalus. Marsh Wren density was negatively correlated with Yellow-headed Blackbird off-bout frequency during the morning (0500-1000), day (1000-1600), and evening (1600-2100), suggesting that Yellow-headed Blackbirds alter their nest attendance behaviour in response to a perceived increased risk of nest predation. We suggest that Yellow- headed Blackbirds are sensitive to nest predation risk and alter their behaviour accordingly to increase overall fitness, although future research is needed to evaluate the influence of Marsh Wren nest predation on the reproductive success of Yellowheaded Blackbirds.

Keywords behaviour, Marsh Wren, parental activity, predation

Disciplines Behavior and Ethology | Ecology and Evolutionary Biology | Natural Resources Management and Policy | Ornithology

Comments This is the peer reviewed version of the following article: Behrens, Colby, Zachary J. Ruff, Tyler M. Harms, and Stephen J. Dinsmore. "Predator density influences nest attendance of Yellow‐headed Blackbirds Xanthocephalus xanthocephalus." Ibis (2019), which has been published in final form at doi: 10.1111/ ibi.12705. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

This article is available at Iowa State University Digital Repository: https://lib.dr.iastate.edu/nrem_pubs/303 This article isThis article by protected copyright. All rights reserved. 10.1111/ibi.12705 differences thisbetween andVersion version the ofRecord.cite Please this asdoi: article the through copyediting, typesetting, pagination and pr This article acceptedhas been for publication andundergone fullpeer review buthasnotbeen Boone, IA50036,USA 2 Hall II, IA2310Pammel Ames, Drive, 50010, USA 1 COLBY BEHRENS xanthocephalus P R Butler Simon : Editor Communication :Short Article type 0000 (Orcid ID : HARMS M. MR. TYLER : (Orcid ID 0000 RUFF JOHN MR. ZACHARY Iowa Department ofNaturalIowa Department Resources, Boone ResearchWildlife Station, 1436 255 EcologyandManagement, ofNatural Department Resource IowaState redator Accepted Articleunning head

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This article isThis article by protected copyright. All rights reserved. or withoutabandonment weobservedfailure physicalevidence, nonestabandonment or nest We analys RESULTS be significant iftheirrespective 95% confidence did intervals not include zero. str andconsidered(AICc) all modelswithintwotop model AICcunitsof ( the goodnesssquare timefor each period. W timeWe evaluated modelsforeach period separately indifferences of thenumber off thenestduringeac sensor was in timethe three periods. Weincluded the densityWren andYellow Team 2016). and JulianDay density,Wren Yellow right models. the

Accepted ong (Burnham support Article average average of number off

- and time period. and time skewed with excess zeroes. Therefore, w The numberof off

ed t We also evaluated the We alsoevaluatedthe effectofquadratic Julian he number of he number off

using - of - fit test. fit test. generalis - headed Blackbird density, Blackbird density, headed Although it is challenging Although it ischallenging causeto attribute aspecific to nest e assessed - - headed Blackbirddensityheaded & bouts bouts - bouts

Anderson Weconsidered covariateAnderson 2002). effects We evaluated modelsusing We evaluated ed - bouts from 52 Yellow frombouts 52 - during eachperiods of time thethree mentionedabove was bouts drivenbydifferencesbouts in thelengthofdatacollection.

linear models b h of the y nest foreachtimeperiody astheresponsevariable inour the fit of log three time three periods - the transformed

e analys with aPoisson distribution ambient temperature ambient top model

on thenumberofoff - , headed B headed

ed the but evaluated thesame

AIC number of thetemperature number hours

for each time each periodusingfor achi adjusted for smallsample for adjusted sizes as an offset to accountfor as anoffset

se data Day andtheinteractionDay of Marsh lackbird as afunctionof

( °C), precipitation°C), (cm), nests, which - Δ bouts

in Program R (R Core Core R(R in Program AICc AICc in top modelsto

seven during e during ≤

2) to have

varied by varied by

Marsh models ach of ach - This article isThis article by protected copyright. All rights reserved. Acceptedperiod andYellow density densityBlackbird 0.06 bouts period ( inacompetingmodel density Additionally, MarshWren wasincludedasaninteractiondensity withYellow periods 1)(Table of the Articlegoodness 25.11 for morning, day,an averageddensity averaged 5.66 temperature birds/ha. 14.42Ambient both andfemales, includes males andduring thedayperiod, of number off asa failure resultdirect ofof atemperature theaddition ; Fig.2 °

in the C, and three . supMarsh Wren wasincludedinthebest density

Δ and . AICc 1.12; = 1) Table - of It was thesole inthetop It was duringthemorningand variable model ) ,

- in acompetitive model( time periods morning ( but did not significant but didnot fit testson 25.13 - bouts (

did not impact o did notimpact - ° headed Blackbird density on Blackbird density headed off C for morning,day,andeveningC for periods,respectively. d eveningperiods,respectively. Nest temperatures averaged23.09 ± β

= the

) was9.82 and was included inacompeting time modelfortheremaining and wasincluded period - 0. 8.84 top model 19 . Marsh Wrendensity for , 95% CI=

( ±

both averaged 2.69birds/ha

ff 5.17 ly -

bout frequency. Likewise,bout frequency. t

( Δ influence offinfluence ± AICc =1.87)AICc forthedaytimeperiod

the day the day ) 4.87 for each timefor each suggested period

during the evening period. evening MarshWrendensity during the - 0.33 )

during themorning time period, during , time - 0. - 04) bouts during theday bouts during - bouts/hour wasnotsignificant bouts/hour period period had and evening(

a si ported modelsforoff

data loggerthe nest. to (Fig. (Fig. 1) ( gnificant negative effecton off Δ AICc =1.16)AICc time andevening he interaction of MarshWren

and Yellow and β

= ° good . - C, 20.95 0.21,95%= CI Yellow

(Table 1)(Table Chi evening time evening time

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This article isThis article by protected copyright. All rights reserved. Accepted the parents. ondensity Yellow overall fitness to furtherresearchisneeded evaluate theimpactof theparents, of MarshWren that indicate decreased off the adaptive responseofYellow intheabsence ofMarshWrenswhichcouldbevaluable bout establishingfrequency in further overall fit 2008 demonstrated Blackbirdsheaded to periodsand eveningtime Article significantlyexhibited feweroff wasasignificantof density predictor Yellow insegregated theirnesting habitats(Leonard respondBlackbirds aggressively to MarshWren (Neudorfpresence 2011) (Bellesspecies topredators both Yellow Marsh Wren Our results DISCUSSION ) , and suggests suggests that Yellow , and ness of anaggressive predator.in thepresence nest suggest

density - in Isles previous research previous research - headed Black that & . P alter

Picman Picman revious studies have shown that Marsh Wrensactassignificantnest revious haveshownthatMarsh studies Yellow - , headed Blackbirds headed

but nottheday during nest attendance nest attendance - bout frequency could the frequency reduce riskof bout andincreasenest predation 1986, - - - bird reproductive headed Blackbirds headed - bouts inareasofhighbouts MarshWrend headed Blackbird behavio Blackbird parental headed headed Blackbirds to nest predation risk. Blackbirds toheaded nestpredation on other species Quinn & strategy inresponseto predationrisk,as - (Bump headed B headed

Holroyd 1989). &

Picman 1986)Picman . This

success (e.g. success alter their their alter nesting behavio 1986 ( Conway lackbird off suggests

Leonard

Ad .

Our study did not examine offstudy didnot Our examine nest survival) andonsurvivalnest survival) of We found that We found

ditionally, Yellow Martin a - n adaptive ability ofn adaptiveability Yellow bout

& u

r ensity duringthemorning Picman is plastic

frequency 2000

and are spatially and are

Whil

, Massaro Massaro , 1986) u

Marsh Wren r

to increase to increase e our study does e ourstudy in responseto - . headed headed

and other and Blackbirds et al.

- -

This article isThis article by protected copyright. All rights reserved. Accepted minimalwere located site because allnestswere atourstudy insimilarhabitat. nestattendance (Conwaycan influence Additionally, differences innestingsubstrate theevaluate impactofMarshWren on density reproductive andadultsurvival. success ofareas highdueMarsh Wrendensity toabund 1984),(Picman 2007). MarshWrensandYellow Because withfemales access greater to foodspend resources less time offthenest(Chalfoun nutritional state offBlackbird this area(Horn1968). other advantagessuchasexploitation in of foodresources,though isneeded research further Article aspreviouslylarge assumed. notmay conferadditionalprotectionfromMarshWrens,o nestingalter behavio 1968(Horn behavio regardless of conspecific This suggests off daytime Although Yellow It u

r thathasevolved is

, Picman , important to Yellow otherfactors haveinfluenced recognize important thatcould - bout frequency, the bout frequency, -

bout frequency thatwere not inourbout female considered frequency study.Forinstance, b alter lackbirds it is thatYellow possible

and foodavailability et al. u

r inresponse

- headed densityheaded Blackbird best wasthesolevariablein model for density. density.

2002 , inpart,asananti

nest attendance nest attendance Colonial nesting in this species may haveevolved nestinginthis Colonial may species of asafunction ). ).

effect of However, our resultsHowever, showtha Yellow to nesting threats, whichto nesting threats,

could influence nest attendance behavio nest could influence - & - headed Blackbird off Blackbird headed headed Blackbirds are Blackbirds acolonialheaded nestingspecies, -

blackbird headed Blackbirds exploit Blackbirds exploit headed similar food resources Martin 2000),although thesedifferences we contend and microhabitat characteristics atthenestsite - predator behaviopredator beha ant food. furtheremphasiz This

vio density u r in response to Marsh Wrenr inresponsetoMarsh presence

r thatthis on off - suggests that blackbird suggests blackbird that colonies bout frequency bout could belowin frequency u t Yellow r during thenesti r during - bouts was not bouts significant. added added - headed headed protection is as not u r

es the need to es theneed

While ambient ambient While B such that lackbirds will ng period - headed headed &

Martin

This article isThis article by protected copyright. All rights reserved. ( twosegregatebreedingknowledge thatthese species territories inco by targeted this aggressive predator. nest study isthefirst,however, to document changes impactspredator on reproductive lifetime outputinbirds. insuspected thestudysystem ifparticularly inparentalactivity changes a We suggestfuturestudiesutili in behavioto investigatechanges nestattendance data loggersfor parental monitoring activity as inWalters c effectively ofdetection smalltemperature fluctuations that inmarsh acontrolloggercould the temperaturesensor provides precise it’sreadings, location 25 (approximately limits km away) logger temp tomonitor ambient particularly those concern. ofconservation through removal predator actions toincreasesuch as in order reproductive output birds, of risk behaviopredation on nestattendance (Conway temperature hasb AcceptedLeonard Article It has been long known that Marsh Wrens depredate nests It longMarshWrensdepredate nests has been that known Our of manybirdspecies. ourresults usingAlthough couldhavebeen by acontroldata intriguing, strengthened

& & Picman

Martin 2000, Walters aptured. et al . een shown by several studies showneen byseveral to drive attendance in severalbird nest species (2

1986

016) Such acontrolallowsprecisionSuch for greater inoncalculating , Harms , Harms .

However, our However, results still demonstratethe of efficacy temperature , z

as this ofinformation couldleadto understanding abetter e this to activity technology measure parental atnests, erature ratherthanthenearby AWOSsensor. & et al.

Dinsmore 2016), behavio demonstrates

2016), studydemonstratedof astronger our influence u This finding, coupledwiththealready finding, This nd subsequentimpacts on success are reproductive

r, afactorthatcouldifneed becontrolled

at nests, andillustrateh in nest attendance behavioin nestattendance u r in response to threatstothenest. r inresponse various

ow such can data beused - occupied marshesoccupied u ral plasticity of ral plasticity u r ina

While the AWOSWhile the -

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and off and

species species have ed - bouts

, This article isThis article by protected copyright. All rights reserved. AcceptedBelles Akaike, likelihoodH. 1973.Informationtheoryandanextension maximum ofthe principle.Pp. REFERENCES ofto improvequality this the manuscript. Log #4 Universityapproved bytheIowaState CareandUse InstitutionalAnimal Committee (IACUC; Honors Program.Undergraduate UniversityThis fundedbyIowaStateUniversity andsupported theIowaState studywas by Article near ofprotection other conspecifics thenest. evenstrategies, fora colonial moreevidencestudy provides onthesignificance of nestpredationinshapingreproductive as HouseWren( specificallyby somespecies inresponseto preda withdif of songbirds in plasticity of threat nestpredationresponse tothe hasbeendemonstrated of as threat blackbirds Marsh Wrens afunctionofthepotential to - - Isl 15 193. Editors).Csaaki, Kiadi,Budapest,Akadeemiai Hungary. 267 es, J.1986.J. C.,andPicman HouseWrennestdestroyingbehavior. Condor88:190 - 8005 -

281

- in Q Troglodytes ). We’re grateful to grateful comments two reviewersfortheirthoughtful ). We’re anonymous

International symposiumon informationtheory,2 ferent types of predators (e.g. offerent types predators aedon - nesting species whichisassumed to nesting species fromtheadded benefit

The work conducted for workconducted this The ; White

Kennedy 1997,Kennedy Ghalambor

tion risk byotheregg

mammalian; Fontaine mammalian;

study was reviewedstudy wasand their nd -

puncturing speciespuncturing such ed. (B.N.PetranandF.

nests & &

Martin 2000).

Martin . by other B ehavio 2006) and

species u ral

Our - This article isThis article by protected copyright. All rights reserved. Accepted Red Grieves, L.A.,protect 2012. andS.Soranests Forbes. Do Ghalambor, risk 2006.predation Fontaine, J.J.,andT.E.Martin. their Parent birdsassessnest andadjust M.,Feast, Conway C. Article Chalfoun, A.D.,Martin. 2007. variationin andT.E. Latitudinal avianincubationattentiveness Bump, S. K.P.,Burnham and D. K.P.J.L. S.T., D. Buckland, Burnham, D.R.Anderson, Laake, information Press,Oxford University New York, New Estimating toIntroduction Sampling: ofBiological Distance Abundance Popula Wren predation?Wren JOrnithol Wilson 60:263 varywithstage nuthatch reproductive strategies. EcolLett the inincubation reductions and food,nest predation. temperature, 54(2): 670 Evolution thefood hypothesis.and atestof limitation Condor 88:328 1986. Yellow R.C. Noble, J., chick embryo.chick JAnat C.K., and T.E. Martin. 2000. Parental investment strategies inC.K., Martin.investmentstrategies and T.E. Parental twoof2000. species and T.E.Martin. - 267. -

theoretic approach.theoretic Springer R. Anderson. 2002. Model selection andAnderson.selection 2002.ModelR. multimodelinference: Apractical

B.K. Speake, B.K. - - headed Bl headed 335.

2000. incubation EvolutionPasserine ofbehavior: of influence

- temperature ongrowthcharacteristics andlipidutilisation in 193: 383 ackbird aggres nest defense: specific risk predation

and M.W.J. Ferguson.

9:428 –

390. 124:188 -

434. York, USA. - Verlag, NewYork, New York,USA. - 190.

Anim Behav Anim

and reproductive effort. Anim Behav effort.AnimBehav and reproductive

1998. The effect of temporary of temporary Theeffect 1998. L. Borchers, andL. Borchers, L.Thomas.2001.

- winged Blackbirds sive responsesto Wrens. Marsh

73:579 - 685. - 585.

from Mars

tions. h This article isThis article by protected copyright. All rights reserved. AcceptedMassaro, M.,A.Starling Martin, T.E.,J. advantageMartin, T.E.1988.On the of N beingdifferent: 2003.Martin, J.,andM. inforest ofpredation typeand Joron. birds:Influence Nestpredator T.A.,Marques, 2007. S.G.of L.Thomas, estimates Fancy, andS.T.Buckland. bird Improving ArticleLeonard, M. J.J.Kent, T.H.,1996. Dinsmore. BirdsinIowa. and bytheauthors,Iow Published Horn, H.S.significanceof 1968. Thecolonial adaptive nestingintheBrewer'sBlackbird 1971. andG.calculation Twiest. Holcomb, L.C., Growthand ofagebyRed T.M.,Harms, andS.J.2016. Spatialscalematterswhenmodelingavianco Dinsmore. nestlings. Bird occurrence. 7:e01288.Ecosphere PLO inducebehavioralpredators changes inparental in care nestSeparating siteandparent bird species. P NatlAcadSci habitatquality.predator’s Oikos102:641 usingdensity Black USA. ( Euphagus cyanocephalusEuphagus S ONE 3:e2331.S ONE L.,

birds spatially segregated?

Scott, and C. Menge. 2000. Nest predation increasesactivity: C.Menge.2000.Nest withparental and Scott, predation and J. Picman. and J. multiple Banding 42:1 - Windhof, J.V. andT.E. Martin.2008. mammalianBriskie, Introduced

- 1986. Why are nesting1986.Why are MarshWrensandYellow covariate sampling. distance Auk 124:1229 ). Ecology49:682 -

85:2196 17. al activity P effects. RSoc

Auk 103:135

- 2199. - 653. -

694 - 140

. est predation andthecoexisteest predation

an endemicNew bird.Zealand London 267:2287 London - - 1243. w inged Bla - headed headed

a City, Iowa, a City, - 2293. - ckbird ckbird nce ofnce

This article isThis article by protected copyright. All rights reserved. Accepted S.L.J.R.B. S.Strindberg, Bishop, Hedley, E.A.J.L. T.A. S.T. Buckland, Thomas,Rexstad, Laake, L., P.D.B.,Skrade, andS.J. Team.R Core forstatistical 2016. Alanguageandenvironment computing. R: for R Foundation Quinn, M. Picman, J.,S.Pribil,A. Isabelle. 2002. value and of colonial Antipredation nesting inYellow ArticlePicman, J.1984. studyon Experimental theroleofintra Olson, C. Neudorf, D. Muchai, M.,and D.L.,Miller, M.L. Burt,E. parental recentdata: developments an sampling surveysforestimat andMarques, K.P. 2010. software: design Burnham. of andanalysis Distance distance theclutches, MountainPlover ( cannourish?young as Ibisthey 91:430 Computing, Austria.Statistical Vienna, 91:206 Blackbirds.headed 119:461 Auk evolution ofnest growt andBlackbirds R. S. , L.H., , C.M. Vleck

and h efficiency. Physiolh efficiency. Biochem Zool – 207.

activity atthe nest.J K.E. Sears, andS.G.Sealy. Sears, K.E. M.A. Plessis. du G.L. Holroyd. G.L.

Yellow Warblers to Wrens.WilsonYellow JOrnitholWarblers , and Dinsmore. A. Rexstad, A. Rexstad, 2013.and L.S Thomas. - destroying be D. Vleck.

1989. Nestling andegg 1989. destructionWrens.Condor byHouse

2005. increases Nest of birdspecies predation with grassland

2012. ing population size.JApplEcol

2006. Periodic cooling of bird eggs reduces embryonic cooling2006. Periodic ofbirdeggsreduces d future directions. Evo d future Methods Ecol Avian Charadrius montanus Charadrius havior Wren in Marsh -

472. Incubation patterns of a shorebird with rapid multiple of withrapid multiple patterns Incubation a shorebird

2011. of Responses nestingYellow Biol

Skutch, A.F.Skutch, 1949.Dotropical birds rearasmany - 455.

79(5):927 36 : 110

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and inter - 936 patial modelsfordistancesampling patial ). CanJ Zool

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- specific competitionspecific in the

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- This article isThis article by protected copyright. All rights reserved. Accepted ArticleWilliams, R., S.L. Hedley,T.A. Branch, M.V. Bravington, A.N. Zerbini,andK. 1997.White, D.W., byand E.D.ofegg nestdestruction Kennedy. Effect coveringandhabitaton L.A.,Walters, J.A.B.A.Jones,andC.L.Volker. Webber, House Wrens. 9 Condor ( Chickadees betwee conservationevaluate stat blue asastudytoChilean whales case illustrateabundance methodstoand estimate n ambient andnest temperature patterns attendance of Carolina incubating Poecile carolinensisPoecile 9:873 us of species.ConservBiol rare -

879. ). Wilson JOrnithol

2016. therelationshipTaking a break:

128:719

25:526 - 726 .

- 535. P. Findlay. 2011.P. Findlay.

This article isThis article by protected copyright. All rights reserved. Accepted Precipitation (cm) ( Temperature Julian Day Julian Day^2 YHBL MAWR MAWR Evening ( Temperature Precipitation (cm) Julian Day Julian Day^2 dens*YHBLMAWR dens dens MAWR YHBL Day ( Temperature Precipitation (cm) Julian Day Julian Day^2 ArticleYHBL MAWR MAWR Morning Covariate represents theindividualmodelweigh the quadratic effect ofJulianDay. density, (1600 Yellow Table 1.

dens dens dens - 2100) periods time atBig inIowa,Wall Lake 2015. - headed Blackbirds duringthemorning(0500 headed dens dens dens dens

‘

Model selection results for covariate effects on selectionresultsforcovariate number theaverage of Model off YHBL dens

*YHBL dens *YHBL *YHBL

° ° ° C) C) C)

dens ’

represents Yellow

‘ k ’

403.84 403.42 401.49 401.23 366.42 364.25 363.13 413.37 413.31 400.42 398.84 365.29 363.67 361.80 375.68 375.47 372.58 371.74 335.71 334.69 333.53 represents thenumberofparameters inthemodel, t, and - headed Blackbird density, Blackbird and headed AICc

‘ cum w ΔAICc 40.72 40.29 38.36 38.11 51.57 51.52 38.63 37.04 42.15 41.94 39.05 38.21 i - ’ 1000), day (1000 1000), day 1.16 0.00 3.30 1.12 0.00 3.49 1.87 0.00 2.18

represents thecumulativemodelweight.

‘ MAWR MAWR 4 2 dens 2 2 2 2 2 4 2 2 2 2 2 4 2 2 2 2 2 2 2 k

- ‘ 1600), and evening andevening 1600), ’ Julian Day^2

represents Marsh Wren 0.30 0. 0.00 0.00 0.00 0.00 0.11 0.32 0.57 0.00 0.00 0.00 0.00 0.11 0.25 0.64 0.00 0.00 0.00 0.00 0.18 53 w i

- ’ bouts/hr by

represents cum w 0.83 0. 1.00 1.00 1.00 1.00 1.00 0.89 0.57 1.00 1.00 1.00 1.00 1.00 0.89 0.64 1.00 1.00 1.00 1.00 1.00 ‘ 53 w i i ’

This article isThis article by protected copyright. All rights reserved. gre densityWren asthesinglecovariate timefor each period, solid line (Day),andevening timemorning (Morn),day (Eve) at period BigWallLakeinIowa, 2015. F andthearea temperature which nest Thewas monitored. blackline solid represents theoutlineofstudy Figure 1. LEGENDSFIGURE Accepted Articleigure y envelope represents interval. the95% confidence 2 . , which was created using the linear , whichwascreatedusingthelinear equation modelthat fromthe Predicted n Predicted Interpolated

black

dots represent locationsof individual umber of off

density inrelation of MarshWrenswithinourarea study on to nests - bouts /hour

as a function of Marsh Wren densityforof Marsh the as afunction Wren

Yellow shows - headed Blackbird Blackbird headed

the point estimatesthe point and

included Marsh nests.