El 29.09.85 es va capturar un siboc a Tiana (Barcelona) que reiniciava una muda interrompuda durant l'hivern. L'ocell havia reactivat la muda des del punt on l'havia aturada a l'hivern, confirmant que aquesta muda interrompuda era un cas de muda suspesa

Tomàs, F. Javier

Revistes Catalanes amb Accés Obert

Butii. GCA 8: 29-31,1991 
I Reactivation of interrupted moult by a Red-necked Nightjar Caprimulgus ruficollis i n  Catalonia (NE Spain) 
F. J. TOMAS 
Reactivation of interrupted moult by a Red-necked Nightiar 
Caprimulgus ruficollis in Catalonia (NE Spain) 
On 29.09.85 at Tiana (Barcelona, NE SpainJ a Red-necked Nightjar 
was captured presenting resurnption of rnoult interrupted during the 
winter. The bird reactivated the rnoult from the point where it had 
stopped in winter, confirming that this rnoult interruption was a case of 
suspended rnoult. 
Key words: Caprirnulgus ruficollis, reactivation of moult, suspended 
moult, Catalonia, NE Spain. 
F. javier Tomas. Escultor Llimona 1 O, 1 er, 1 a. 0803 1 Barcelona. 
Rebut: 13.01.92; Acceptat: 2 1 0 2  92  
First winter and adult Red-necked Nightiar 
undergo a complete moult in the wintering 
areas in Africa (Cramp 1985). Nevertheless, 
first winter birds and at least some adults (Euring 
code 6) interrupt moult, before replacing the 
outerrnost primaries (Cramp 1985, G. Gorga- 
Ilo com. pers.). Although this moult has been 
considered qsuspended)) (Cramp 1985), in 
fact, it is unknown if this is a suspended moult 
(finished at breeding grounds) or an arrested 
moult (reactivating the interrupted moult, without 
continuing the preceding moult). 
On 29th September 1985 atTiana, Borce 
lona (4 1.29N 02.16E) I netted a Red-necked 
Nightjar in active moult. Although it was not 
possible toage the bird exactly, itwas nota bird 
in its first year. The moult score for each prima y 
is shown in Table 1 .  
00th the innermost and outermost prirnaries 
were scored as ({old)), since both had not yet 
been renewed in the autumn moult that the bird 
was undergoing. However, the seven inner- 
most primaries of both wings were newer than 
the outermostones showing that there were two 
different generations of ((old)) primaries, the 
innermost corresponding to feathers moulted 
the preceding winter, and the outermost corres- 
ponding to feathers left unmoulted, after the 
interruption of the complete winter moult. In the 
tai1 the central pair of rectrices were in active 
moult, but there were no differences in the wear 
of the old feathers. 
From this data, it can be concluded that this 
bird had interrupted its moult during the winter 
beforefinishing the replacementof theoutermost 
primaries (the outermost three) and later resu- 
med moult from the point it was stopped. This 
seems to confirm that the interruption of moult by 
Butll. GCA 8.1991 
I 
PRIMARIES i 
Wing PI P2 P3 P4 P5 P6 P7 P8 P9 PI0 
Right 0 0 0 0 0 0 0 4  
Left 0 0 0 0 0 0 0 5 0 0 ~  
Table 1. Moulting score of each primary for both wings. Moult score according to Ginn & 
Melviile (1983), counted ascendantly. 
Taula 1. Puntuaci6 de la muda de les primdries de cada ala. Puntuació segons Ginn b Melville (1983), 
comptades ascendentment. 
Red-necked Nightjars during winter is actually 
a suspended moult strategy: 
ACKNOWLEDGEMENTS 
Gabriel Gargallo provided me detailed 
information about moult in this species and 
reviewed the draft. 
RESUM 
Reactivació d'una muda interrompuda 
en un Siboc Caprimulgus ruficollis a Cata- 
lunya. 
Els Sibocs adults i del primer hivern realit- 
zen una muda completa a les urees d'hivernada 
a IIAfrica (Cramp 1985). Els joves, pero i 
almenys, una part dels adults (G. Gargallo 
com. pers.), interrompen aquesta muda abans 
de renovar les primaries més externes (Cramp 
1985, G.Gargallo com. pers.). Tot i que 
aquesta interrupció ha estat qualificada de 
muda suspesa, es desconeix si és en realitat 
una muda suspesa (que els ocells acaben a les 
urees de cria), o bé una muda arrestada. 
N 29.09.85 es va capturar a Tiana (Bar- 
celona) un Siboc aduh (codi Euring 4) en muda 
activa (vegeu taula 1 ) .  Tant les primaries inter- 
nes com les més externes foren valorades com 
a c velles^, ja que ambdues no havien estat 
renovades en la muda de tardor que aquell 
ocell estava duent a terme. Tanmateix, les set 
primaries internes  velles^^ de les dues ales eren 
més noves que les més externes ~vellesw, Fet que 
indicava que hi havia dues generacions dife- 
rents de primaries avelles~; les més internes 
corresponien a plomes mudades durant l'hivern 
precedent i les més externes eren plomes 
deixades sense mudar després de la interrup- 
ció de la muda completa de I'hivern. 
Aquest patró de desgast i de muda corres- 
pon a un ocell que havia interromput la renova- 
ció de les primaries durant I'hivern, deixant les 
tres més externes sense mudar, i que, ara, un 
cop finalitzada la cria, la reiniciava des del 
punt on va ser aturada. Aixo sembla comfirmar 
que la interrupció de la muda durant l'hivern per 
part del siboc és una estrategia de muda 
suspesa. 
REFERENCES 
CRAMP, S.  1985. The Birds of the Wes- 
tern Palearctic. Vol. 4. Oxford: Oxford Univer- 
sity Press. 
Moult by a Red-necked Nightjar 
GARCIA, E. 1984. Siboc Caprimulgus GINN, H.B. & MELVILLE, D.S. 1983. 
ruhcoh. ln Muntaner,,., Ferrer, X. &Martinez- Moult in birds. Guide 19. Tring: BTO. 
Vilalta, A. (eds.). Atlas dels ocells nidificants de 
Catalunya i Andorra. p. 141-1 42. Barcelona: 
Ketres. 


Reactivation of interrupted moult by a Red-necked Nightjar (Caprimulgus ruficollis) in Catalonia (NE Spain)

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