Journal of Archaeological Science 38 (2011) 3541e3548

Contents lists available at SciVerse ScienceDirect

Journal of Archaeological Science

journal homepage: http://www.elsevier.com/locate/jas

Bone damage patterns found in the avian prey remains of crested

caracara Caracara plancus (Aves, Falconiformes)
Claudia I. Montalvoa, *, Pedro O. Talladea, Fernando J. Fernándezb, c, Germán J. Moreirab, c, d,
Daniel J. Rafusee, Luciano J.M. De Santisb
a
Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina
b
Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Cátedra de Anatomía Comparada, 64 entre diagonal 113 y 120, 1900 La Plata, Buenos Aires, Argentina
c
CONICET, Consejo Nacional de Investigaciones Científicas y Tecnológicas, Argentina
d
CIC, Comisión de Investigaciones Científicas de la provincia de Buenos Aires, Calle 526 entre 10 y 11, 1899 Tolosa, Buenos Aires, Argentina
e
Facultad de Ciencias Sociales, Universidad Nacional del Centro de la Provincia de Buenos Aires, Av. Del Valle 5737, 7400 Olavarría, Buenos Aires, Argentina

a r t i c l e i n f o a b s t r a c t

Article history: The following paper presents the results of the analysis of the avian prey bones found in uneaten remains
Received 20 December 2010 of crested caracara (Caracara plancus, Aves, Falconiformes) from La Pampa province, Argentina.
Received in revised form Anatomical parts representation and taphonomic modifications were evaluated and compared to results
12 August 2011
of the evaluation of bone remains recovered from crested caracara’s pellets and to previous studies of
Accepted 18 August 2011
other diurnal birds of prey. The results suggest a preferential consumption of some body parts of avian
prey, as evidenced in the high frequency of wing elements in the uneaten prey remains. This analysis
Keywords:
helps to support interpretative data concerning the origins of avian remains in the zooarchaeological and
Taphonomy
Caracara plancus
paleontological record, and contributes to the knowledge of a common predator found throughout
Falconiformes diverse environments in South America.
Avian bones Ó 2011 Elsevier Ltd. All rights reserved.
Uneaten prey remains
Pellets

1. Introduction archaeological site (Laguna El Sosneado-3) in southern Mendoza,

and compared those results with bone assemblages originated by
From a zooarchaeological and paleontological perspective, nocturnal bird of prey (possibly Tyto alba). It is only recently that
understanding the origins of meso and microvertebrate bone studies which assess taphonomic accumulations of avian remains
accumulations is of great interest. Although avian remains are have become more frequent, many of which attempt to establish
generally less numerous than those of mammals, the information whether accumulations are of human origin or are produced by
that they can provide should not be discarded (Bochenski, 2005). some predator or scavenger (Bochenski, 2005; Bochenski and
Actualistic studies documenting taphonomic patterns on avian Tomek, 1994, 1997; Bochenski and Nekrasov, 2001; Bochenski and
remains created by raptors and carnivorous mammals can help us Tornberg, 2003; Bochenski et al., 1993, 1997, 1998, 1999, 2009;
to understand how the zooarchaeological and paleontological Laroulandie, 2002).
records have formed. However, taphonomic studies of avian In this paper, we present the analysis performed on the avian
remains are scarce in South American literature. In several of her remains accumulated by crested caracara (Caracara plancus, Falco-
publications, Cruz (2003, 2005, 2007, 2008) has devoted time to the nidae), well-known in Argentina as “carancho”; and which has
analysis of taphonomic processes that affect avian remains by a wide distribution in South America (Dove and Banks, 1999). These
evaluating the anatomical part representation and other tapho- species nest and roost mostly in trees, and studies of their feeding
nomic modifications found in avian remains. However, her studies habits define them as an opportunistic predator that habitually
focused mainly on species from Patagonia. Elsewhere, Fernández feeds on carrion (White et al., 1994; Travaini et al., 2001 and liter-
et al. (2009) evaluated small avian accumulations from an ature therein). Carrion constitutes between 20 and 40% of their diet
(Rodríguez Estrella and Rivera Rodríguez, 1997; Travaini et al.,
2001; Morrison and Pias, 2006; Vargas et al., 2007), while the
* Corresponding author. Tel.: þ54 2954 436787; fax: þ54 2954 433079. remainder of their diet consists of hunting live prey. Rodríguez
E-mail address: cmontalvo@exactas.unlpam.edu.ar (C.I. Montalvo). Estrella and Rivera Rodríguez (1997) found that this species

0305-4403/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jas.2011.08.021
3542 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548

normally hunted prey with a body mass of less than 500 g,

including small rodents, lagomorphs, birds, amphibians, reptiles
and fish. Vargas et al. (2007) mentioned that birds were consumed
in low proportions.
Generally, it is common to see crested caracara occupying urban
and suburban areas, likely the result of natural attraction to waste
left by human’s. As mentioned in previous works (White et al.,
1994; Yorio and Giaccardi, 2002), some diurnal raptor (e. g.
crested caracara), frequently take advantage of human waste.
Likewise, such a situation may have occurred in the past, where
groups of crested caracara came to waste dumps for food and any
accumulation would have mixed with the human derived waste.
In the context of taphonomic studies of prey consumed by C.
plancus, we analyzed avian remains produced by this predator.
Although small mammals are the most frequent prey found in the
samples (pellets and uneaten prey remains), avian remains were
also present and constituted more than 45% of the vertebrate
remains consumed in the sampling time. Previous taphonomic
analysis was performed on the non ingested rodent prey as well as
the recovered rodent remains found in the pellets of this predator
(see Montalvo and Tallade, 2009, 2010). The analysis demonstrated
that C. plancus not only produces strong modifications in the bones
of its ingested prey, but also generates bone accumulations of
uneaten prey remains with particular anatomical representation,
breakage patterns and without evidence of corrosion by digestion.
Results also suggested that C. plancus performs a selective
consumption of some anatomical parts of the rodent prey, while
discarding others (Montalvo and Tallade, 2009, 2010).
This study provides data regarding the consumption of avian
prey by the C. plancus in central Argentina. The results derived from
the analysis of the modifications that this predator produces on the Fig. 1. Geographic location of Santa Rosa in La Pampa province, Argentina.
bones of the avian prey are also presented.

2. Material and methods examined all the avian bones using the methodology proposed by
Bochenski (2005) and Bochenski et al. (2009 and references
The uneaten prey remains sample was collected every week therein).
between February 2005 and March 2008, from an area just outside In order to evaluate the minimal number of individuals (MNI)
the city of Santa Rosa, La Pampa, Argentina (36 370 1000 S, 64190 4500 of the uneaten prey remains, each fragmented or whole avian
W) (Fig. 1). All remains of the vertebrate prey were produced by skeletal element (articulated or isolated) collected in each
two crested caracara. In this work we assessed only the remains of sampling date was considered as one individual. In cases where
the avian prey. the remains of more than one individual were collected,
In the sampling time, 111 uneaten avian remains were recov- anatomical and taxonomic representation helped to discern if the
ered. Of these, 76 individuals were identified and evaluated while sample contained multiple individuals. Thus, the total MNI of 76
the remaining 36 specimens were identified as feathers. Twenty- corresponds to the sum of all individuals, and given the continuity
three pellets from the two crested caracara that contained avian of the samples, this number adjustably represented the minimal
bones were also evaluated. The pellet sample was collected every quantity of consumed avian prey during the collection period. The
week from March to June 2005. number of identified specimens (NISP) and the minimum number
Uneaten prey remains and pellets were recovered in small of elements (MNE) for each type of bone was evaluated by taxon
superficial areas accumulated directly under trees of caldén (Pro- (Nothura spp., Columba spp. and “other taxa”). The total is equal to
sopis caldenia), chañar (Geoffroea decorticans), and eucalyptus the sum of complete bones and proximal or distal parts e
(Eucaliptus spp.). These trees are commonly used for alimentation whichever is more numerous (Grayson, 1984; Lyman, 1994). The
and regurgitation perches for this raptor (POT pers. obs.). MNI for the pellets sample was evaluated considering the element
All bone remains were analyzed under a Leica Ms5 binocular with the highest skeletal frequency (tarsometatarsus) (Grayson,
microscope and some of them were photographed under a Jeol 35 1984; Lyman, 1994).
CF at 8 kV at the “Unidad de Administración Territorial (UAT) - The relative abundance of skeletal elements was calculated for
Centro Científico y Tecnológico CONICET Bahía Blanca”, in Bahía the bones from the uneaten prey remains and the bones recovered
Blanca, Argentina. from the pellets, taking into consideration the MNI of each sample.
All identifiable avian bones from the uneaten prey remains and In the case of the uneaten prey remains, the different skeletal
pellets were anatomically and taxonomically identified with elements grouped by taxon were also analyzed. The evaluated
a comparative collection from the “Cátedra de Anatomía Com- categories were Nothura spp., Columba spp. and "other taxa". Since
parada, Facultad de Ciencias Naturales y Museo, UNLP”, as well as the relative abundance does a good job of showing the proportion
a modern osteological bird collection from the “División Paleon- of each of the preserved elements, and in view of the fact that the
tología Vertebrados, Museo de La Plata (UNLP)” and “Facultad de number of uneaten prey remains evaluated is known, the MNI by
Ciencias Exactas y Naturales, UNLPam”, and a private collection of skeletal element was not calculated (Bochenski, 2005 and
one of the authors (POT). For the taphonomic analysis, we references therein). The following equation was used: MNEi/
 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548 3543

(EixMNI)  100 where MNEi is the minimum number of particular Table 2

skeletal elements in the sample, and Ei is the expected number of Number of identified specimens NISP and minimum number of elements (MNE)
recovered from the uneaten prey remains and their relative abundance considering
that skeletal element per individual (Andrews, 1990). a minimal number of individuals (MNI) of 76.
The following indexes were calculated: (a) to give an idea of the
differential preservation of wings and legs (Ericson, 1987): Element NISP MNE Relative abundance

(humerus þ ulna þ carpometacarpus)/(humerus þ ulna þ Mandible 12 12 7.89

Maxilla 10 10 13.16
carpometacarpus þ femur þ tibiotarsus þ tarsometatarsus) X 100; (b)
Scapula 42 41 26.97
to evaluate the preservation of proximal and distal elements Coracoid 45 45 29.61
(Bochenski y Nekrasov, 2001): (scapula þ coracoideum þ Furcula 8 8 5.26
humerus þ femur þ tibiotarsus)/(scapula þ coracoideum þ Sternum 30 30 39.47
humerus þ femur þ tibiotarsus þ ulna þ radius þ carpometacarpus Humerus 59 58 38.16
Radius 33 33 21.71
þ tarsometatarsus)  100; and (c) to evaluate the preservation of core Ulna 30 30 19.74
and limb elements (Bochenski, 2005): (sternum þ pelvis þ scapula Carpometacarpus 18 18 11.84
þ coracoideum)/(sternum þ pelvis þ scapula þ coracoideum Pelvis 22 22 28.95
þ humerus þ ulna þ radius þ carpometacarpus þ femur þ tibiotarsus Femur 15 13 8.55
Tibiotarsus 16 16 10.53
þ tarsometatarsus)  100. The ratios of proximal and distal portions of
Fibula 4 4 2.63
long bones (Bochenski, 2005) were analyzed in order to observe the Tarsometatarsus 10 10 6.58
difference between whole bone and proximal parts as well as whole Phalange 150 150 4.93
bone and distal parts. The degree of bone breakage was analyzed taking Other bones 176
into consideration the percentage of whole bones and the total of each
type of long bone recovered.
In reference to the avian bones preserved in the pellets, the least abundant elements. The most frequently found elements were
degree of digestion was assessed by analyzing the cortical surface the sternum, humerus, coracoids, scapula, and pelvis.
and the breakage edges (Bochenski and Tomek, 1994; Bochenski With respect to the differential representation of skeletal
and Tornberg, 2003; Bochenski et al., 1993, 2009). elements according to the taxon, the relative abundance was
Finally, a chi-square test was used to evaluate the possible analyzed for Nothura spp. (MNI ¼ 21, MNE ¼ 106, average relative
deviation of wing to leg elements, proximal to distal elements, and abundance ¼ 13.99%), Columba spp. (MNI ¼ 18, MNE ¼ 190, average
core to limb elements from the expected 1:1 proportion. relative abundance ¼ 27.73%), and “other taxa” (MNI ¼ 37,
MNE ¼ 204, average relative abundance ¼ 13.46%). Fig. 2 shows the
3. Results differential representation of skeletal elements for these three
categories.
Seventy six uneaten avian remains were recovered in the The frequency of articulated skeletal elements may be related to
sampling time (Table 1). The majority of the identified individuals the degree of completeness in the sample. In 50% of the individuals,
were Nothura spp. and Columba spp. There were however a high the most numerous fragments were those of the pectoral girdle and
percentage of individuals represented by isolated skeletal elements wings (Fig. 3A), while 25% were from the posterior region. In four
(27.63%), and these could only be assigned to the taxonomic cate- individuals, the skull was found complete and articulated with the
gory Aves indet. mandibles. The hemimandibles were found articulated among
In total, 680 skeletal remains were recovered (NISP). This value themselves in only one individual.
includes all indeterminable bone fragments, vertebrae fragments, In total, 30 sternum were recovered and five of them were found
ribs, and remains of cranial bones which were not analyzed here whole (Fig. 3B). When the posterior body region was present, the
(“other bones” in Table 2). From the total NISP, an MNE of 500 pelvis, as well as the synsacrum was preserved in all of the indi-
skeletal elements was calculated (Table 2) that included 150 viduals (Fig. 3C); whole in three individuals, and articulated with
phalanges (60% feet and 40% wings). the leg in two individuals.
In order to evaluate the relative abundance of skeletal elements, The degree of bone completeness was also analyzed. The scap-
each element was assessed taking into consideration the total MNI ulas were recovered mostly broken, and the coracoids were the
of 76 (Table 2). With an average relative abundance of 17.25%, this skeletal elements most commonly found whole (Table 3). In
indicates a low representation of all the skeletal elements. Along reference to the broken long bones, upon analysis of the fracture
with the leg elements, the mandibles and furculas are among the type, there was a clear predominance of spiral fractures (sensu

Table 1
List of uneaten avian remains recovered and the minimal number of individuals
(MNI) evaluated for each taxa.

Taxon MNI
Tinamiformes Nothura spp. 21
Rhynchotus rufescens 2
Charadriiformes Larus spp. 2
Anseriformes Anas platalea 1
Anas spp. 1
Falconiformes Falco sparverius 1
Strigiformes Athene cunicularia 5
Columbiformes Columba spp. 18
Psittasiformes Aratinga acuticaudata 1
Cuculiformes Guira guira 1
Passeriformes Sturnella spp. 1
Furnarius rufus 1
Aves indet. 21 Fig. 2. Percentage of differential representation of skeletal elements according to the
taxon of the uneaten prey remains.
3544 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548

Fig. 3. A. Columba sp. girdle and wings; B. Rhynchotus rufescens whole sternum; C. Columba sp. whole synsacrum; D. Aves indet. humerus with spiral fracture; E. Columba sp. broken
sternum; F. Columba sp. sternum with steeped fractures. Scale bar ¼ 1 cm.

Marshall, 1989) identified in 85% of this elements (Fig. 3D), fol- of humerus showed signs of bone perforations. This feature was
lowed by a low percentage of stepped (7.5%) and longitudinal also frequent in the sternum (n ¼ 10), principally on the keel and
fractures (7.5%). the borders of these elements presented steeped fractures that
Wing elements represented 72.29% of the sum of wing and leg appeared to have habitually collapsed within the different sectors
bones, which was highly statistically significant (c2 ¼ 12.773, (Fig. 3E,F).
P < 0.01, df ¼ 1) and deviated from the expected 50% (1:1 A total of 408 avian remains recovered from the 23 pellets were
proportion). Proximal elements of the skeleton represented 66.04% evaluated. An MNE of 296 and an MNI of 6 was calculated (based on
of the sum of proximal and distal elements (Table 4), which was the tarsometatarsus), but more than 50% of the bones could only be
also highly statistically significant (c2 ¼ 7.9324, P < 0.01, df ¼ 1) and assigned to Aves indet. The average relative frequency of each
deviated from the expected 50% (1:1 proportion). The relationship registered skeletal element was 26.61%. No mandible, maxilla,
in preservation between the core and limb elements was 43.43%, furcula, sternum, radius, pelvis, or fibula bones were recovered in
which indicated a better representation of core elements, was this sample. The most frequent elements were the tarsometatarsus,
statistically significant (c2 ¼ 1.3258, P < 0.05, df ¼ 1), and deviated tibiotarsus, phalanges (95% from the feet) and femur (Fig. 4).
from the expected 50% (1:1 proportion). The number of articulated skeletal elements found in the pellets
Finally, 21 elements presented some form of perforations with was high. Preserved elements included three complete autopodials,
rounding or sub-rounding along the edges. These holes were nor- two scapulas and articulated coracoids, 21 groups of phalanges, and
mally found on the irregular borders and collapsed sections of the three groups of vertebra. Although complete elements were
fractured bones. They were recorded at different locations in four abundant (mainly phalanges), only one carpometacarpus, and
skull bones: the orbital bone, the maxilla, and the cranium. Two a complete coracoid could be identified (Table 5). Some retaining
pelvis elements were also heavily affected by perforations. In skin, muscle, and tendons were also recovered which likely pre-
addition, the distal end of a tibiotarsus, the proximal end of vented their disarticulation.
a coracoid, and along the proximal and distal ends of two fragments The wing/leg index was calculated to 22.85%, which deviated
from the expected 50% (1:1 proportion) and was highly statistically
Table 3
Degree of completeness in the uneaten prey remains sample. Table 4
Percentage of preserved long bone portions in the uneaten prey remains sample.
Element MNE % Whole bone
Scapula 42 30.95 Element % Proximal elements % Distal elements
Coracoid 45 91.11 Scapula 93.18 97.73
Humerus 59 62.71 Humerus 91.07 75.00
Ulna 30 63.33 Ulna 73.33 90.00
Radius 33 69.7 Radius 81.82 87.88
Carpometacarpus 18 66.67 Carpometacarpus 72.22 94.44
Femur 15 53.33 Femur 84.62 76.92
Tibiotarsus 16 56.25 Tibiotarsus 75.00 81.25
Tarsometatarsus 10 80.00 Tarsometatarsus 100 80.00
 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548 3545

Bochenski et al. (1993) and Laroulandie (2002) find in their samples

of owl species (Bubo bubo). The scarce or lack of fibula in the
uneaten prey remains and pellets samples may be related to their
bone fragility.
The sternum, humerus, coracoids, and pelvis were the most
abundant elements recovered from the uneaten prey remains.
These four elements were also the most abundant in samples of
uneaten prey remains from diurnal birds studied by Bochenski et al.
(1999). Results from this author (Bochenski, 2005; Bochenski et al.,
2009) indicate that the high frequency of sternum is a typical
characteristic of uneaten prey remains of diurnal bird of prey. The
high abundance of coracoids is also coherent with data collected by
Fig. 4. Frequency of skeletal elements from the pellets sample based on the MNI of 6 Bochenski (2005). With respect to the ulna, Bochenski (2005) found
and an MNE of 296.
that this element is frequent in uneaten prey remains of various
species of owls and diurnal raptors; however it does not exceed 15%
significant (c2 ¼ 7.7946, P < 0.01, df ¼ 1), suggesting an elevated
of the C. plancus uneaten prey remains sample.
abundance of leg elements in the pellet sample. The relation
The low frequency of the cranium, mandible, and maxilla is an
between proximal and distal skeletal elements showed the same
attribute present in uneaten prey remains of C. plancus that coin-
proportion. The results from the evaluation of the proximal and
cides with other diurnal raptor (Bochenski, 2005). There was also
distal portions of the long bones are shown in Table 5. With the
a clear absence of cranial and mandible elements in the pellets. In
exception of the tibiotarsus and tarsometatarsus, the proximal
this sense, the pellets sample differ slightly from samples of various
portions were the most abundant portions recovered. The relation
species of owls and gyrfalcon (Falco rusticolus) analyzed by
between core elements with respect to limb elements was calcu-
Bochenski (2005), which show some proportions of these
lated to 7.89%, which also deviated from the expected 50% (1:1
elements. Though it was mentioned in some cases (gyrfalcon in
proportion) and was highly statistically significant (c2 ¼ 20.637,
Bochenski et al., 1998) that the low frequency of these elements in
P < 0.01, df ¼ 1), indicating a better representation of limb bone
pellets and uneaten prey remains are from the disarticulation of the
elements. In all of the bone remains, evidence of corrosion by
head by the falcons; in the case of C. plancus, there is no evidence or
digestion was high, especially on the surface and breakage borders
bibliographic data that indicates this type of behavior.
of bones (Table 6 and Fig. 5).
Some skeletal elements of uneaten prey remains were still in
articulation, mainly the pectoral girdle and wings. Evaluation of the
4. Discussion
bone breakage in this sample demonstrates that the coracoids were
the less effected, while the scapulas were frequently broken. The
Although it would be premature to disregard the possibility of
avian scapulas are fragile elements, thus a high fragmentation
scavenging, the continuity in the recollection of the uneaten prey
frequency is expected.
and the pellets samples indicates that there was no scavenger
Fig. 7 shows a comparison between the percentages of the
activity beyond that of the crested caracara. In reference to the
complete bone in the uneaten prey remains of C. plancus and the
taphonomic analysis, none of the elements showed signs of
bibliographic data of other diurnal bird of prey (Bochenski et al.,
weathering. In many cases the skin, feathers, and scales may have
1997, 1999; Laroulandie, 2002; Bochenski and Tornberg, 2003).
protected the bones from such agents, or the foliage from the tress
Bochenski (2005) divided the birds of prey in three groups
may have slowed the weathering process.
taking into consideration the grade of bone breakage in prey. The
Among the uneaten prey remains, Nothura spp. and Columba
first group included all diurnal raptor considering the bones found
spp. were the more frequent taxa. In particular, Columba has one of
in their pellets. In this category, a high percentage of broken bones
the higher body masses (350e450 g) in the sample. It also has the
were registered. In contrast, the category of less modification also
greatest anatomical representation and its skeletal representation
included diurnal raptor when the uneaten prey remains were
could indicate that its body was only partially consumed. From the
considered. Accordingly, similar results were found when consid-
bones recovered in the pellets sample, bone breakage and digestive
ering the fragmentation caused by C. plancus.
corrosion made it difficult to assign taxonomic categories. Although
Results from the wing/leg index indicate a higher abundance
the results from the pellets sample should be taken with caution
of wing elements in the uneaten prey remains sample. When
because the sample is small, the data indicates that C. plancus
comparing this data with the bibliographic records (Bochenski
modified the ingested bones of their avian prey. Results also show
et al., 1997, 1999; Laroulandie, 2002; Bochenski and Tornberg,
important differences in the anatomical representation with
2003; Bochenski, 2005), there is a clear resemblance with
respect to the sample of the uneaten prey remains (Fig. 6).
other diurnal raptors, especially with the prey remains of
Among the remains recovered from the pellets, the tarsome-
F. rusticolus (Fig. 8). In reference to the pellets sample, the results
tarsus were the most frequent leg elements, a pattern which both
obtained in this index (higher abundance of leg elements) differ
Table 5
from the owl and diurnal raptor pellet values mentioned by
Percentages of proximal and distal long bone portions in the pellets sample. Bochenski (2005) with equality or predominance of wing bones.
Furthermore, in archaeological assemblages accumulated by
Element MNE % Proximal % Distal.
elements elements
humans, Ericson (1987) found a predominance of leg elements.
This author indicates that the abundance of wing elements is
Coracoid 3 100 33.33
Humerus 1 100 0 characteristic of natural context of depositation. However,
Ulna 4 50.00 50.00 Livingston (1989) recorded a similar avian skeletal part
Carpometacarpus 3 100 33.33 frequency between natural and anthropic context. In addition,
Femur 6 66.66 33.33 Livingston (1989) and Cruz (2005) have suggested that bird bone
Tibiotarsus 9 37.50 62.50
Tarsometatarsus 12 30.00 70.00
structure and functional anatomy are important factors affecting
the skeletal part representation. Elsewhere, Bovy (2002)
3546 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548

Table 6
Percentages of corrosion by digestion and degree of breakage in bones recovered of the pellets sample.

Bone surface Breakage

Undamaged Rounded Sharp Rounded

MNE % MNE % MNE % MNE %

Vertebra 22 100 7 100
Ribs 4 100
Scapula 2 100 2 100
Coracoid 3 100 2 100
Humerus 1 100 1 100
Ulna 1 25.00 3 75.00 3 75.00 25.00
Carpometacarpus 3 100 2 100
Femur 6 100 6 100
Tibiotarsus 9 100 2 22.20 7 77.80
Tarsometatarsus 12 100 9 75.00 3 25.00
Phalanges 125 56.30 97 43.70 6 35.30 11 64.70
Unidentifiableshafts 4 50.00 4 50.00 4 50.00 4 50.00
Total(MNE ¼ 296) 45.30 54.70 44.30 55.70

proposed that the bone mineral density can not explain the were not affected. This in turn made it difficult to observe possible
abundance of wings found in numerous archaeological sites taphonomic modifications in elements recovered from the pellets
from the Pacific Northwest Coast of USA. samples. In bones of uneaten prey remains, mainly the sternum
The relation between proximal and distal skeletal elements showed some dissolution holes as well as other marks produced
demonstrates a clear abundance of proximal elements among during consumption. During taphonomic studies performed on
uneaten prey remains; while in the pellets sample, the proximal penguin (Spheniscus magellanicus) breeding colonies in Patagonia,
and distal elements showed the same proportion. In reference to Cruz (2007) observed various avian carcasses that had taphonomic
this characteristic, results from Bochenski (2005) indicate that modifications principally concentrated in the sternum and keel.
three groups of avian predators can be distinguished. When the Based on their described characteristics, these modifications are
pellet remains are evaluated, C. plancus would fit into the first similar to those found in C. plancus sample.
group. This group included diurnal bird of prey when only their Superficial marks were likely to have been produced by the
pellets are considered (ratio1:1). However, with the evaluation of claws or beaks during the processing of the prey (Bochenski et al.,
uneaten prey remains, this species also fits into the third group 2009), including breakage and bone collapse marks found on the
(that included golden eagle, Aquila chrysaetos), mainly because the sterna and pelvis. It is interesting to note that perforations of these
proximal skeletal elements are the most frequent. elements has not been recorded from human’ bird assemblages,
The relation between the core and limb elements showed indicating that this feature could be a tool to distinguish nonhuman
a greater representation in the core elements from the uneaten predation (Bochenski et al., 2009). Moreover, the sterna and pelvis
remains and limb elements from the pellets sample. These results of birds recovered from archaeological sites in Argentina are very
were similar with those mentioned by Bochenski (2005) who low and do not have these types of marks (e.g. Cruz, 2003, 2006;
indicated that in remains recovered from pellets of owls and birds Fernández et al., 2009; Giardina, 2010; Prates and Acosta
of prey, limb elements greatly predominate, while a high propor- Hospitaleche, 2010). Marks found close to the epiphysis on long
tion of core for uneaten prey of golden eagle. bones are commonly found on the prey of other diurnal raptors
Digestive traces are one of main diagnostic characteristic for
distinguishing animal predation from human hunting (Andrews,
1990). As previously indicated, the greater proportion of the
elements recovered from the pellets sample presented evidence of
digestion. Only the elements that were found protected by skin

Fig. 5. Skeletal elements of Aves indet. recovered from the pellets sample with
evidence of corrosion by digestion A. humerus; B. indet. shaft; C. femur; D. indet. shaft. Fig. 6. Minimum number of elements (MNE) distribution in uneaten prey remains and
Scale bar ¼ 1 mm. pellets sample.
 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548 3547

sternum, humerus, and other wing elements. There was also

a higher abundance of complete bones and a greater frequency of
long bone proximal ends. In reference to the presence of holes and
other damage marks, these appeared to be influenced by the
differential bone survivorship and density of the elements.
Furthermore, the majority of these marks were only observable on
the sternum. The indexes and taphonomic analysis of the sample of
prey remains are consistent with the results of previous studies on
diurnal birds of prey (i.e., Bochenski, 2005 and literature therein;
Bochenski et al., 2009).
Although the pellets sample was small, the results showed
a high frequency of leg elements, particularly the tarsometa-
tarsus and feet phalanges. There was also a general absence of
mandibles, maxilla and other cranial elements, furculas, sterna,
radius, pelvises and fibulas. Also scarce were any complete
elements, with the exception of the articulated phalanges which
Fig. 7. Comparison of percentages of complete bone found in uneaten prey remains of
were likely protected by the skin of the prey. There was a slightly
C. plancus with other diurnal bird of prey taken by Bochenski et al. (1997, 1999),
Laroulandie (2002) and Bochenski and Tornberg (2003).
higher frequency of long bone proximal epiphysis, and as pre-
dicted, there was a high abundance of digestively corroded
elements.
As seen in other diurnal raptor studies (i.e., Bochenski, 2005;
Bochenski et al., 2009) C. plancus appears to affect the bones of
its avian prey in a differential mode, which causes a skeletal
element representation pattern when the prey has been consumed
and deposited in a pellet or when uneaten prey parts are left
behind. In consequence, the eating habit of this diurnal raptor
affects both what is found in the pellets as well as accumulations of
the uneaten prey remains. Given the frequency and characteristics
of both samples, the uneaten prey remains provide a strong basis
for analysis. Taphonomic analysis by Montalvo and Tallade (2009,
2010) of consumed rodents by C. plancus indicates that the mix-
ing of remains from pellets and uneaten prey remains can cause
interpretative errors, such as attributing the skeletal representa-
tions to more than one predator.
When considering the results of Bochenski et al. (1998) and
Bochenski (2005), C. plancus would be catagorized as a maximum
modifier of bones of its digested avian remains and a slight modifier
of those uneaten prey remains. Thus, C. plancus can be added in the
listing presented in Bochenski et al. (2009) as a raptor which
produces marks on bones of its uneaten prey remains.
Bearing in mind that the number of avian remains in the
archaeological and paleontology record is generally small
compared to mammals, this analysis helps to support interpretive
Fig. 8. Proportion of the total number of wing (humerus, ulna, carpometacarpus) to leg data concerning their origins. More specifically it could be used as
(femur, tibiotarsus, tarsometatarsus) bones in uneaten prey remains compared with
an actualistic model and help contribute to the knowledge of
data of other diurnal birds.
a common predator found throughout diverse environments in
South America.
(Bochenski and Tornberg, 2003; Bochenski et al., 2009). It is
however interesting to make note of the perforations found on the
distal end of the humerus. Laroulandie (2005) mentions that Acknowledgments
disarticulation of a bird skeleton by humans may produce holes in
the fossa olecrani of the humerus. She observed that the marks This work was funded by a Project developed at the “Facultad de
produced by beaks are related to the bones capacity to withstand Ciencias Exactas y Naturales, Universidad Nacional de La Pampa”.
this type of mechanical pressure (Laroulandie, 2002). Thus, the Special thanks are given to I. Cruz for her comments on a first
evidence for this type of damage is scarce in long bones, which tend version of the manuscript, E. Braun for her help with the English
to be denser and less likely to collapse under pressure. The differ- version and Claudia Tambussi to permit the consultation of the
ential bone density could also explain the low presence of these comparative material (MLP). We finally thank two anonymous
types of marks throughout the samples. reviewers for their comments and suggestions that greatly
improved this paper.
5. Conclusions
References
Results from this analysis help to identify and classify the
characteristics of prey bones which have been either digested or Andrews, P., 1990. Owls, caves and fossils. Predation, preservation, and accumula-
tion of small mammal bones in caves, with the analysis of the Pleistocene cave
discarded by the crested caracara. Among those bones recovered faunas from Westbury-sub-Mendip. The University of Chicago Press, Somerset,
from the uneaten prey remains, there was a high frequency of UK, 231 p.
3548 C.I. Montalvo et al. / Journal of Archaeological Science 38 (2011) 3541e3548

Bochenski, Z.M., 2005. Owls, diurnal raptors and humans: signature on avian bones. Fernández, F.J., Moreira, G.J., Ballejo, F., De Santis, L.J.M., 2009. Novedosos registros
In: O’Connor, T. (Ed.), Biosfere to Lithosfere. New Studies in Vertebrate de aves exhumadas del sitio arqueológico "Laguna El Sosneado (LS-3)" para el
Taphonomy. Oxbow Books, Oxford, pp. 31e45. Holoceno tardío en el sur de Mendoza: aspectos tafonómicos. Intersecciones en
Bochenski, Z.M., Boev, Z., Mitev, I., Tomek, T., 1993. Patterns of bird bone frag- Antropología 10, 329e345.
mentation in pellets of the Tawny Owl (Strix aluco) and the Eagle Owl (Bubo Giardina, M., 2010. El aprovechamiento de la avifauna entre las sociedades
bubo) and their taphonomical implications. Acta Zoologica Cracoviense 36 (2), cazadoras-recolectoras del sur de Mendoza: un enfoque arqueozoológico. Ph.D.
313e328. thesis, Facultad de Ciencias Naturales y Museo, Universidad Nacional La Plata.
Bochenski, Z.M., Huhtala, K., Jussila, P., Pulliainen, E., Tornberg, R., Tunkkari, P.S., Grayson, D.K., 1984. Quantitative Zooarchaeology: Topics in the Analysis of
1998. Damage to bird bones in pellets of Gyrfalcon Falco rusticolus. Journal of Archaeological Faunas. Academics Press, Orlando, Florida.
Archaeological Science 25, 425e433. Laroulandie, V., 2002. Damage to pigeon long bones in pellets of the eagle owl Bubo
Bochenski, Z.M., Huhtala, K., Sulkava, S., Tornberg, R., 1999. Fragmentation and bubo and food remains of peregrine falcon Falco peregrinus: zooarchaeological
preservation of bird bones in food remains of the golden eagle Aquila chrys- implications. Acta Zoologica Cracoviense 45 (special issue), 331e339.
aetos. Archaeofauna 8, 31e39. Laroulandie, V., 2005. Anthropogenic versus non-anthropogenic bird bone assem-
Bochenski, Z.M., Korovin, V.A., Nekrasov, A.E., Tomek, T., 1997. Fragmentation of bird blages: new criteria for their distinction. In: O’Connor, T. (Ed.), Biosphere to
bones in food remains of imperial eagles Aquila heliaca. International Journal of Lithosphere. New Studies in Vertebrate Taphonomy. Oxbow Books, Oxford,
Osteoarchaeology 7 (2), 165e171. pp. 25e30.
Bochenski, Z.M., Nekrasov, A.E., 2001. The taphonomy of sub-Atlantic bird remains Livingston, S.D., 1989. The taphonomic interpretation of avian skeletal Part fre-
from Bazhukovo III, Ural Mountains, Russia. Acta Zoologica Cracoviense 44 (2), cuencies. Journal of Archaeological Science 16, 537e547.
93e106. Lyman, R.L., 1994. Vertebrate Taphonomy. Cambridge University Press, Cambridge.
Bochenski, Z.M., Tomek, T., 1994. Pattern of bird bone fragmentation in pellets of the Marshall, L., 1989. Bone modification and "The laws of burial". In: Bonnichsen, R.,
Long-eared Owl Asio otus and its taphonomical implications. Acta Zoologica Sorg, M.H. (Eds.), Bone Modification. People of the Americas Publications.
Cracoviense 37 (1), 177e190. University of Main, p. 535.
Bochenski, Z.M., Tomek, T., 1997. Preservation of bird bones: erosion versus diges- Montalvo, C.I., Tallade, P.O., 2009. Taphonomy of the accumulations produced by
tion by owls. International Journal of Osteoarchaeology 7 (4), 372e387. Caracara plancus (Falconidae). Analysis of prey remains and pellets. Journal of
Bochenski, Z.M., Tomek, T., Tornberg, R., Wertz, K., 2009. Distinguishing nonhuman Taphonomy 7 (2e3), 235e248.
predation on birds: pattern of damage done by the white-tailed eagle Haliaetus Montalvo, C.I., Tallade, P.O., 2010. Análisis tafonómico de restos no ingeridos de
albicilla, with comments on the punctures made by the golden eagle Aquila roedores presa de Caracara plancus (Aves, Falconidae). In: De Nigris, M.,
chrysaetos. Journal of Archaeological Science 36, 122e129. Fernández, P.M., Giardina, M., Gil, A.F., Gutiérrez, M.A., Izeta, A., Neme, G.,
Bochenski, Z.M., Tornberg, R., 2003. Fragmentation and preservation of bones in Yacobaccio, H.D. (Eds.), Zooarqueología a principios del siglo XXI: aportes
uneaten food remains of the Gyrfalcon Falco rusticolus. Journal of Archaeolog- teóricos, metodológicos y casos de estudio. Ediciones del Espinillo, Buenos
ical Science 30, 1665e1671. Aires, Argentina, pp. 419e428.
Bovy, K.M., 2002. Differential avian skeletal part distribution: explaining the Morrison, J.L., Pias, K.E., 2006. Assesing the vertebrate component of the diet of
abundance of wings. Journal of Archaeological Science 29, 965e978. Florida's Crested Caracaras (Caracara cheriway). Florida Scientist 69 (1),
Cruz, I., 2003. Paisajes tafonómicos de restos de Aves en el sur de Patagonia 36e43.
continental. Aportes para la interpretación de conjuntos avifaunísticos en reg- Prates, L., Acosta Hospitaleche, C., 2010. Las aves de sitios arqueológicos del Hol-
istros arqueológicos del Holoceno. Ph.D. thesis, Facultad de Filosofía y Letras, oceno tardío de Norpatagonia, Argentina. Los sitios Negro Muerto y Angostura 1
Universidad de Buenos Aires, 652 pp. (Río Negro). Archaeofauna 19, 7e18.
Cruz, I., 2005. La representación de partes esqueléticas de aves. Patrones naturales e Rodríguez Estrella, R., Rivera Rodríguez, L.B., 1997. Crested caracara food habits in
interpretación arqueológica. Archaeofauna, International Journal of Archae- the Cape region of Baja California, Mexico. Journal of Raptor Research 31 (3),
ozoology 14, 69e81. 228e233.
Cruz, I., 2006. Los restos de pingüinos (Spheniscidae) de los sitios de Cabo Blanco Travaini, A., Donázar, J.A., Ceballos, O., Hiraldo, F., 2001. Food habits of the Crested
(Santa Cruz, Patagonia Argentina). Análisis tafonómico y perspectivas arqueo- Caracara (Caracara plancus) in the Andean Patagonia: the role of breeding
lógicas. Intersecciones en Antropología 7, 15e26. constraints. Journal of Arid Environments 48, 211e219.
Cruz, I., 2007. Avian Taphonomy: observations at two Magellanic penguin (Sphe- Vargas, R.J., Bó, M.S., Faver, M., 2007. Diet of the southern caracara (Caracara
niscus magellanicus) breeding colonies and their implications for the fossil plancus) in Mar Chiquita Reserve, southern Argentina. Journal of Raptor
record. Journal of Archaeological Science 34, 1252e1261. Research 41 (2), 113e121.
Cruz, I., 2008. Avian and mammalian bone taphonomy in Southern Continental White, C.M., Olsen, P.D., Kiff, L.F., 1994. Falcons. In: del Hoyo, J., Elliott, A., Sartagal, J.
Patagonia. A comparative approach. Quaternary International 180, 30e37. (Eds.), Handbook of the Birds of the World. New World Vultures to Guinea Fowl,
Dove, C.J., Banks, R.C., 1999. A taxonomic study of crested caracaras (Falconidae). vol. 2. Lynx Editions, Barcelona, Spain, pp. 216e275.
Wilson Bulletin 111 (3), 330e339. Yorio, P., Giaccardi, M., 2002. Urban and fishery waste tips as food sources for
Ericson, P.G.P., 1987. Interpretations of archaeological bird remains: a taphonomic birds in Northern Coastal Patagonia, Argentina. Ornitología Neotropical 13,
approach. Journal of Archaeological Science 14, 65e75. 283e292.