科创中国

Contrary?to?the?nestling?phase,?the?post-fledging?phase?has?been?less?studied?probably?because?it?is?challenging?to?follow?the?chicks?after?they?fledge.?However,?this?phase?is?crucial?to?consider?when?focusing?on?the?life?cycle?of?individuals?because?it?is?associated?with?new?demands:?After?leaving?the?nest,?individuals?have?to?find?their?own?food?and?cope?with?a?new?set?of?previously?unknown?stressors.?In?this?study,?we?aimed?at?better?understanding?how?energetically?demanding?the?post-ftedging?period?is?in?house?sparrows?Passer?domesticus?by?measuring?several?indices?of?a?fledgling's?state?(body?condition,?fat?and?muscle?scores?and?plumage?quality).?If?the?energetic?demands?of?the?post-fledging?period?are?greater?than?those?of?the?adult?life,?we?predicted?that?fledglings?should?be?in?lower?condition?and?should?have?a?plumage?of?lower?quality?relative?to?adults.?Supporting?this?prediction,?the?condition?and?the?plumage?of?fledglings?differed?dramatically?from?those?of?adults.?Interestingly,?this?difference?disappeared?in?autumn.?Overall,?our?results?suggest?that?the?post-fledging?period?is?probably?one?of?the?most?energetically?demanding?of?the?life?cycle?in?this?species.?Supporting?this?idea,?the?resighting?probability?of?fledglings?was?lower?relative?to?adults.?However,?resighting?probability?depends?on?many?factors?(mortality,?dispersal,?habitat?use?and?behaviours)?and?future?studies?are?necessary?to?tease?apart?their?relative?importance?in?determining?resighting?probability?[Current?Zoology?60?(4):?449-459,?2014].

Conservation?of?endangered?sympatric?species?must?be?carefully?executed?to?ensure?that?the?protection?of?one?species?does?not?negatively?impact?the?survival?of?another.?Critically?endangered?Pecos?gambusia?Gambusia?nobilis?and?Leon?Springs?pupfish?Cyprinodon?bovinus,?which?are?endemic?to?a?threatened?desert?spring?habitat,?exemplify?one?such?scenario.?Recently,?this?habitat?has?been?expanded,?and?captively?bred?C.?bovinus?were?released?to?repopulate?an?area?historically?known?to?contain?this?species.?A?previous?study?suggested?that?G.?nobilis?are?detrimental?to?C.?bovinus?populations,?due?to?their?tendency?to?congregate?near?spawning?pairs?and?feed?on?their?eggs.?Whether?G.?nobilis?are?attracted?to?territorial?C.?bovinus,?regardless?of?spawning?behavior,?remains?unclear.?To?determine?this,?the?number?of?G.?nobilis?in?occupied?and?unoccupied?breeding?territories?of?both?wild?and?captively?bred?C.?bovinus?was?measured.?Gambusia?nobilis?densities?were?similar?between?unoccupied?and?occupied?territorial?sites,?suggesting?that?they?do?not?show?a?preference?for?C.?bovinus?territories.?Regardless?of?habitat?location?or?prior?captivity,?territorial?C.?bovinus?significantly?excluded?G.?nobilis?within?their?direct?vicinity?(5?cm),?but?not?from?their?entire?territory.?Decreased?G.?nobilis?density?within?the?habitat?may?allow?C.?bovinus?to?defend?their?breeding?territories?more?readily?during?the?summer?spawning?season.?This?study?provides?empirical?evidence?of?captively?raised?individuals?behaving?similarly?to?wild?indi-?viduals?upon?reintroduction?to?their?natural?habitat?and?support?for?conservation?methods?that?focus?on?common?limiting?factors?between?endangered?species?[Current?Zoology?60?(4):?527-533,?2014].