En una menjadora situada als Pirineus es van investigar les interaccions socials entre mallerengues petites i emplomallades d'edat i estatus coneguts prèviament. De manera similar a estudis anteriors, la relació de dominància entre les dues espècies no va ser clara, i en determinades ocasions un mascle adult de mallerenga petita va desplaçar una femella jove de mallerenga emplomallada d'una menjadora. Es discuteixen els factors que poden estar al darrere de les desviacions detectades respecte d'una jerarquia basada en la mida de les dues espècies

Brotons, Lluís

Revistes Catalanes amb Accés Obert

Butll. GCA 14: 69-72,1997 
I Notes on the social status of the Coal Tit Parus afer and the Crested Tit Parus cristafus in the Pvrenees 
L. BROTONS 
Social interactions between Coal and Crested Tits of known age 
and residence status were investigated at a feeder in the Pyrenees. 
In accordance with previous studies, the relation between these two 
species was not clear-cut, since at the feeder an adult male Coal Tit 
was able to dominate a yearling female Crested Tit. Site-related 
dominance was probably the main cause for the detected deviation 
from the generally recognised size-related hierarchy in these two 
species 
Key words: Coal Tit, Parus ater, Crested Tit, Parus cristatus, 
hierarchy, dominance, Pyrenees. 
Lluís Brotons. Dept. Biologia Animal (Vertebrats). 
Facultat de Biologia. Univ. de Barcelona. 
Av. Diagonal, 645. 08028 Barcelona. 
E-mail: brotons@porthos.bio.ub.es 
Rebut: 09.1 2.97; Acceptat: 31.03.98 
Species of smaller size have typically 
been considered subordinate in social 
hierarchy to larger birds. It is commonly 
accepted that the Coal Tit Parus ater (mean: 
9.3 g), due to its small size, is subordinate 
to both the Crested Tit Parus cristatus (mean: 
1 1.2 g) and the Willow Tit Parus montanus 
(mean: 11.5 g), as well as to the other tit 
species (Dhondt 1989, Suhonen et al. 
1992). However, as pointed out by Haftorn 
(1 993), few data exit on the issue, and the 
results of his study suggest that the social 
status of the Coal Tit requires further 
consideration. In Haftorn's study, the Coal 
( Tit was found to be dominant over the 
larger Willow Tit in most cases. Due to the 
importance of dominance in interspecific 
competition for food and foraging sites 
among the tit guild (Dhondt 1989), data 
on this topic are of great interest. The 
observations of Kallander (1 997) on a Coal 
Tit that dominated both Blue Parus caeruleus 
and Great Tits Parus major also suggest that 
dominance relationships may not always 
be related to body size. 
In this paper, I present data on 
interspecific interactions between Coal and ( Crested Tits at an artificial feeder. Birds were 
Butll. GCA 14. 1997 
of known sex, age and size, which, it was 
felt, might help to elucidate the nature of 
the interspecific interactions observed. 
Data were collected at on artificial tem- 
porary feeder provided with fat, located in 
the "Parc Natural Cadi-Moixeró", Pyrenees 
(46" 83' N, 4" 08' E) in an urea 1950 m 
above seu-level and surrounded bv 
Mountain Pine Pinus uncinata forest mixed 
secondarily with Scots Pine Pinus sylvestris. 
Observations were collected during the 
winter 1995 -96 ,  f r om November to  
January. Only Crested and Coal Tits visited 
the feeder; these are the only tit species 
regularly present in the urea during winter. 
All birds were colour-ringed, and the usual 
morphometrical measurements were taken 
each time they were captured. Birds were 
sexed according to their behaviour during 
the breeding season and o n  size 
differences, and  aged according to 
Svensson ( 1  992) .  Observations were 
collected during four sessions of 1 hour, 
with the observer situated 10 m from the 
feeder. 
During the sessions, visits by birds were 
recorded, especially those which involved 
both species. In 70  visits were recorded (26 
by Coal Tits and 44 by Crested Tits). When 
two birds visited the feeder simultaneously, 
a bird was considered to be dominant if: 
( 1 )  i t  chased the other away; (2 )  i t  
supplanted the other; (3) the other withdrew 
on its approach; or (4) the other waited 
nearby until the dominant bird left. Only 
interactions with a clear and unequivocal 
outcome were included in the analyses. 
Four Crested Tits and two Coal Tits were 
observed during the sessions. A total of 15 
intraspecific (which served to establish the 
hierarchy wi th in species) and  1 6  
interspecific interactions between Coal and 
Crested Tits were recorded. The Crested Tits 
were not clearly dominant over the Coal 
Tits, although most Crested Tits won the 
interactions with Coal Tits (1 1 vs. 5 times, 
sign-test= 1.55, N.S.). However, of six inter- 
actions between a young female Crested 
Tit (the smallest of the four, tarsus length 
17.7 mm vs. x= 19.0 mm, mean for the 
other three) and an adult male Coal Tit 
(tarsus length 17.2 mm), the latter won four 
(sign test= 0.60, N.S.). It also made 
significantly more attacks on its opponent 
than did the Crested Tit (6 vs O, sign test= 
2.04, p<0.05), although in some cases the 
Crested Tit continued feeding on the fat. 
The adult male Crested Tit which visited the 
feeder won seven out of eight interactions 
over the adult female Coal Tit (7 vs 1, sign- 
test= 1.76, p=0.07). The other interadions 
between Coal  and Crested Tits were, 
unfortunately, few and ambiguous. 
These observations support the idea that 
the Crested Tit is generally dominant over 
the Coal Tit. Also recorded were mixed 
winter flocks, where Crested Tits won all of 
the eleven recorded conflicts (1 1 vs. O). 
However, the data presented show that on 
some occasions Coal  Tits can defeat 
Crested Tits at especially rich food sources. 
Haftorn (1993) raised the possibility that 
factors other than size were related to 
dominance in the hierarchy of tits he 
studied. Different experiments on tits have 
shown that when checking for factors such 
as size or age, prior residence determines 
dominance (Koivula et al. 1993, Sandell & 
Smith 1989). These experiments, carried 
out with both Willow and Great Tits Parus 
major, suggest that pay-off asymmetries 
dependent on previous experience rather 
than theoretical fighting potential (¡.e. size 
or age) determine rank within these species, 
and that prior residence often overrides 
advantages of size and age (Koivula et al. 
1993). The two Coal Tits in my study had 
been ringed four years earlier as juveniles 
a few metres from where the feeder was 
placed, whereas all but one of the Crested 
Tits were juveniles. 
Therefore, it seems feasible that the 
adult male Coal Tit had a higher position 
in the hierarchy, as an effect of prior 
Social status of Tits in the Pyrenees 
residence, which compensated for the bird's 
smaller size and enabled it to win most of 
the interactions with one of the Crested Tits, 
a juvenile female. The fact that the Coal 
Tits used attacks (more costly to individuals, 
Lemel & Wallin 1993), causing juvenile 
Crested Tits to retreat from the feeding pla- 
ce, seems to reinforce the view of a higher 
position of the adult Coal Tits in the 
hierarchy. In this way, Coal Tits may 
occasionally gain access to important 
resources, which compensate for the energy 
invested in making the attacks. Differences 
in motivation due to differences in food 
deprivation may occasionally lead to 
switches in a linear hierarchy, potentially 
resulting in observations similar to mine 
(Lemel & Wallin 1993). 
Bearing in mind that most Crested Tits 
were dominant over Coal Tits, the fact that 
adult Coal Tits may be able to defeat young 
Crested Tits in agonistic interactions ut a 
concentrated food source is of great 
interest, because it raises the issue that site- 
related dominance or differences in 
motivation might switch positions in size- 
related hierarchies within, but also between, 
species. 
During winter, Coal and Crested Tits use 
pine cones as an important food source, and 
cones rich in ~ i n e  seeds could be a location 
where the kin'd of interactions referred to in 
this paper may become important. As stated 
by Haftorn, more experimental data on 
interspecific encounters between tits are 
needed to determine the inters~ecific rank 
order of tits, because this hierarchy is  likely 
to depend on several factors and thus may 
not always be the same: 
ACKNOWLEDGEMENTS 
I am grateful to the staff of the "Parc 
Natural del Cadi-Moixeró" for their help in 
the field. Raimon Marine raised some points 
which improved earlier drafts of the 
manuscript. The fieldwork received financial 
support from the Parc Natural del Cadi- 
Moixeró. During the study I was supported 
by a gran.t from the Comissionat per a 
Universitats i Recerca de la Generalitat de 
Catalunya. 
RESUM 
Notes sobre I'estatus social de la 
Mallerenga Petita Parus ater i la Malle- 
renga Emplomallada Parus cristatus als 
Pirineus 
En una menjadora situada als Pirineus 
es varen investigar les interaccions socials 
entre mallerengues petites i emplomallades 
d'edat i estatus coneguts previament. De 
manera similar a estudis anteriors, la relació 
de dominancia entre les dues especies no 
va ser clara, i en determinades ocasions un 
mascle adult de Mallerenga Petita va 
desplacar una femella jove de Mallerenga 
Emplomallada d'una menjadora. Es 
discuteixen els factors que poden estar al 
darrere de les desviacions detectades res- 
pecte d'una jerarquia basada en la mida 
de les dues especies. 
REFERENCES 
DHONDT, A. 1989. Ecological and 
evolutionary effects of interspecific 
competition in tits. Wilson Bull. 101 (2): 
198-21 6. 
HAFTORN, S. 1993. Is the Coal Tit, 
Parus ater, the most subordinate of the 
Scandinavian tits? Ornis Scand. 24 (4): 
335-338. 
GLLANDER, H. 1997. En dominant 
svartmes Parus ater. Ornis Svecica 7: 37. 
KOIVULA, K., LAHTI, K., ORELL, M. & 
RYTKONEN, S. 1993. Prior residency as a 
Butll. GCA 14, 1997 
key determinant of social dominance in the 
Willow Tit (Parus montanus). Behav. Ecol. 
Sociobiol. 33: 283-287. 
LEMEL, J. & WALLIN, K. 1993. Status 
signalling, motivational condition and 
dominance: an experimental study in the 
Great Tit, Parus major L. Anim. Behav. 45: 
549-558. 
SANDELL, M. & SMITH, H.G. 1991. 
Dominance, prior occupancy, and winter 
residency in the Great Tit (Parus major). 
Behav. Ecol. Sociobiol. 29: 147-1 52. 
SVENSSON, L. 1992. ldentification 
Guide to European Passerines. 4th edition. 
Stockholm: Svensson. 
SUHONEN, J., ALATALO, R.V., 
CARLSSON, A. & HOGLUND, J. 1992. 
Food resource distribution and the 
organization of the Parus guild in a spruce 
forest. Ornis Scand. 23: 467-474. 


Notes on the social status of the Coal Tit (Parus ater) and the Crested Tit (Parus cristatus) in the Pyrenees

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