Filling latitudinal gaps in Tachycineta swallows: reproductive strategies in a South American species

SILVINA IPPI; VALERIA OJEDA; NATALIE DUDINSZKY; MILENA CIERI; BRUNO RIOVITTI; VALENTINA FERRETTI; MELINA BARRIONUEVO

EMU

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2024

0158-4197

Chileanswallows (Tachycineta leucopyga) arethe southernmost swallows in the Tachycinetagenus, breeding from central Chile to southern Chile and Argentina. Previousstudies, which focused on a population breeding at 54°S in Tierra del Fuego,Argentina, revealed differences in life-history traits compared to their NorthernHemisphere congeners. Notably, Chilean swallows exhibit smaller clutch size,and greater male nest attendance during the incubation period than theirnorthern congeners, among other differences. It has been suggested that thesevariations could be adaptations for breeding in an extreme environment. Toassess the consistency of these patterns for the species, we studied itsbreeding biology and parental care in north-western Argentine Patagonia (41°S).If the breeding traits observed in the austral population accurately reflectthose of the species as a whole, we predict a smaller clutch size, higherfemale reproductive investment, and similar nest attendance by both sexesduring incubation compared to other Tachycinetapopulations breeding at similar northern latitudes. Furthermore, we expectto observe a negative correlation between clutch size, egg size, and breedingsuccess with laying date, consistent with the typical pattern observed in Tachycineta species, including Chileanswallows. Surprisingly, clutch and egg sizes did not differ between northernand southern Patagonian populations. We did not find evidence of a negativerelationship between clutch or egg size and laying date (neither between firstand second/replacement clutches). Male nest attendance during incubation wasvariable and low, but they fed nestlings at rates similar to those of females.These findings suggest that Chilean swallows adopt variable reproductivestrategies in different areas. This may help this species adapt to differentenvironments and climates, ranging from the shorter breeding seasons and lowersummer mean temperatures of Tierra del Fuego to the longer breeding seasons andhigher seasonal and daily thermal amplitudes at continental north AndeanPatagonia.@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:swiss;mso-font-pitch:variable;mso-font-signature:-469750017 -1040178053 9 0 511 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;margin-left:0cm;line-height:115%;mso-pagination:widow-orphan;mso-hyphenate:none;font-size:11.0pt;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:Calibri;mso-bidi-theme-font:minor-bidi;mso-ansi-language:EN-GB;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:11.0pt;mso-ansi-font-size:11.0pt;mso-bidi-font-size:11.0pt;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:Calibri;mso-bidi-theme-font:minor-bidi;mso-font-kerning:0pt;mso-ligatures:none;mso-ansi-language:EN-US;}.MsoPapDefault{mso-style-type:export-only;mso-hyphenate:none;}div.WordSection1{page:WordSection1;}