PRESENCE OF BONE REMAINS IN THE OSSUARIES OF BEARDED VULTURES ( GYPAETUS BARBATUS ): STORAGE OR NUTRITIVE REJECTION? ANTONI MARGALIDA 1 Bearded Vulture Study and Protection Group, Apdo. 43 E-25520 El Pont de Suert, Lleida, Spain Abstract.—Ossuaries, or bone-breaking sites, are used by Bearded Vultures ( Gypaetus barbatus) to prepare and store bone re- mains. �e di�erent nutriti�e �alues o� di�erent parts o�t�e skeleton and bones and t�e �a�t t�at many remains stay in t�e ossuary �or �e di�erent nutriti�e �alues o� di�erent parts o� t�e skeleton and bones and t�e �a�t t�at many remains stay in t�e ossuary �or long periods wit�out being �onsumed suggest t�at t�ey may �a�e anot�er use besides storage. � tested w�et�er t�e presen�e o� bone . � tested w�et�er t�e presen�e o� bone � tested w�et�er t�e presen�e o� bone remains in ossuaries may result �rom sele�tion (“nutrient �on�entration” �ypot�esis) and reje�tion o� bone remains on t�e basis o� nu- triti�e �alue. O� t�e remains �ound at t�e study sites, 84.9% belonged to medium-sized ungulates, 11.6% to large mammals, 2.5% to �arni�ores, and 1 % to Suidae. Bone remains �ound were prin�ipally s�apulas (14.9%), �ertebrae (13.2%), skulls (12.5%), tibias (10.7%), mandibles (9.3%), ribs (8.3%), and �umeri (7.2%). �e larger proportion o� less-nutritious skeletal parts (i.e., �ontaining less olei� a�id) and t�e signi i�antly smaller proportion o� distal epip�yses, w�i�� are more nutritious, support t�e nutrient �on�entration �ypot�esis. On t�e ot�er �and, t�e s�ar�e presen�e o� remains o� large mammals and Suidae and t�e �ig� presen�e o� s�apulae, �ertebrae, and skulls suggest t�at �andling ei�ien�y �an also inluen�e �ood sele�tion. Bone sele�tion based on nutriti�e �alue may allow Bearded Vultures to optimize parental �oraging e�ort and maximize itness. Received 12 July 2007, accepted 31 October 2007. Key words: Bearded Vulture, bone-breaking sites, �ood pre�eren�es, �oraging t�eory, Gypaetus barbatus, nutriti�e sele�tion, ossuaries. Presencia de Restos Óseos en Rompederos de Gypaetus barbatus: ¿Almacenaje o Rechazo Nutritivo? Resumen.—Los rompederos son lugares utilizados por Gypaetus barbatus para romper, preparar o alma�enar los restos óseos. El di�erente �alor nutriti�o de las di�erentes partes anatómi�as del esqueleto y de los �uesos, y el �e��o de que los �uesos puedan perman- e�er meses sin ser �onsumidos, sugieren la posibilidad de que exista una expli�a�ión alternati�a al alma�enaje. En este artí�ulo e�alúo si la presen�ia de restos óseos en los rompederos puede ser resultado de una sele��ión pre�ia (�ipótesis de la �on�entra�ión de nutri- entes) y si el re��azo de algunos restos óseos podría ser �onse�uen�ia de su es�aso �alor nutriti�o. El 84.9% de los restos en�ontrados pertene�ieron a ungulados de tamaño medio, el 11.6% a mamí�eros de gran tamaño, el 2.5% a �arní�oros y el 1% a Suidae. Los restos óseos en�ontrados �ueron prin�ipalmente es�ápulas (14.9%), �értebras (13.2%), �ráneos (12.5%), tibias (10.7%), mandíbulas (9.3%), �os- tillas (8.3%) y �úmeros (7.2%). La aso�ia�ión negati�a entre una mayor propor�ión de partes esqueléti�as �on menor �ontenido nutriti�o (i.e., menor �ontenido de á�ido olei�o), así �omo la menor propor�ión signi i�ati�a de epí isis distales (más nutriti�as), apoyan la �ipóte- sis de la sele��ión nutriti�a. Por otro lado, la es�asa presen�ia de restos de grandes mamí�eros y Suidae y la gran presen�ia de es�ápulas, �értebras y �ráneos sugieren que la ei�ien�ia en la manipula�ión también puede inluir la sele��ión de los �uesos. La sele��ión nutriti�a de los �uesos puede permitir a Gypaetus barbatus optimizar el es�uerzo parental de �orrajeo y maximizar su ade�ua�ión biológi�a. — 560 — he Auk 125(3):560–564, 2008  �e Ameri�an Ornit�ologists’ Union, 2008. 2008. Printed in USA. 1 E-mail: margalida@in�.entorno.es he Auk, Vol. 125, Number 3, pages 560–564. �SSN 0004-8038, ele�troni� �SSN 1938-4254. �SSN 1938-4254. 1938-4254.  2008 by �e Ameri�an Ornit�ologists’ Union. All rig�ts reser�ed. Please dire�t all requests �or permission to p�oto�opy or reprodu�e arti�le �ontent t�roug� t�e Uni�ersity o� Cali�ornia Press’s Rig�ts and Permissions website, �ttp://www.u�pressjournals. �om/reprint�n�o.asp. �O�: 10.1525/auk.2008.07124 �O�: 10.1525/auk.2008.07124 �n several species t�at �at�� and �onsume t�eir �ood, prey pro�essing �as been �onsidered an important be�a�ior, in w�i�� t�e animal remo�es parts o� t�e �ar�ass t�at �ould �inder digestion or waste digesti�e energy or t�at, as a �onsequen�e o� t�eir mor- p�ology, �ould damage t�e digesti�e tra�t (Kaspari 1991). �is be- �a�ior allows t�ese spe�ies to optimize bot� t�e energy gained �rom �ood and t�e time spent �oraging (Kaspari 1991, Ydenberg 1998). �e Bearded Vulture (Gypaetus barbatus) is a bone-eating spe�ies t�at in�abits mountainous regions o� Europe and A�ri�a (Hiraldo et al. 1979). �ts diet is bone remains o� medium-size 1979). �ts diet is bone remains o� medium-size ts diet is bone remains o� medium-size ungulates (see Margalida et al. 2007); t�ere�ore, one o� t�e ��ar- a�teristi�s o� its be�a�ioral e�ology is t�e preparation o� t�e remains in t�e ossuaries, or bone-breaking sites (Boudoint 1976, Margalida and Bertran 2001). �ese are ro�ky sur�a�es w�ere Bearded Vultures deliberately drop bones, and entire animal �ar- �asses, �rom a �eig�t w�ile lying to break up t�e remains. �is be- �a�ior allows t�e bird to �ragmentize bones t�at, be�ause o� t�eir lengt� or widt�, �annot be swallowed, and to break up t�e di �- �erent parts o� a skeleton. Apart �rom t�e breaking or separation o� bone remains, ossuaries are also used to store bone remains