THE MAJELLA OF

H v t r i , ~ . (n.j.1 9 ( I 2) (1997). 23-2Y

USE OF A GARBAGE DUMP BY SOME MAMMAL SPECIES IN THE MAJELLA MASSTF (ABRUZZO, ITALY)

A LDO MARTINA( *) AN D M ONICA GALLARATT(**)

ABSTRAC‘I’ - I n several previous works the presence o f urban solid wastes in the feeding habits of some animal species has been docunicnted. This study was carried out to discover which specie, vi- sit a rubbish dump located in :in area of the Majella massif. Monthly nightiiue direct ohmvations, from September 1990 to May 1992, revealed the presence of dogs Cmis

,fiimi/iorix, domestic cats F a l i ~ [si/\!esrri.s] cati4s. wolves Ca1ri.c l~ipirs and red foxcs Vr41pe.y i > u / p e c . The lox was the most frequently observcd species. Fox visits to the dump wcrc distributed more continuously during the en- tire period of thc study then the other species. An “asymmetry analysis” was carried out to find out the animals’ favourite tiiiie to use the dump. Thc analysis produced time lag values of 02:00 A.M. to 05:OO A.M.

The wolf was observed the least. During the monthly observation\ a similar trend between the cat and wolf came to light. The two species also visited the dump at similar timcs (wolf O7:OO-1 1:OO P.M.:

cat: OS:OO-lO:OO P.M.).

Dog visits to the dump were Icss continuous i n comparison with other species: no preferred time was revealed.

Some environrncntal factors. related to the geographical area and management oC the dump limited waste avrzilability. This probably had an effect on the presence of the animals.

Krp wordy: Waste dump, Cui?is I r r p i i s , Cani.5 [/rr~~~i”l~~/tirmi/iui.i.y, Felis [ s i h ~ 7 s t i . i s j cotii.s. L/>i/pe.~ ~ ~ [ / p s , Majella massif, ltaly

INTRODLCTION

L!rban rubbish dumps rcpresent a considera- ble source of alinientary subsistence both due to their easy accessibility and for their incxhaustibility. This is why they attract se- veral animal species very strongly. Some of these species feed directly on human meal left-overs ( c . g. insects, rodents). Others usc the dump as a hunting ground (e. g. noctur- nal and diurnal raptors, insectivorous birds), or for both the above pui-poses (e. g. crows, domestic cats. wolves. foxes). Several past studies have reported the prcsence of waste in the feeding habits of some animal species.

In particular it has been demonstrated how common waste is present in the diet of some

rnammals (e. g. Scott a n d Causey. 1973;

Macdonald ct al., 1980; Prigioni et al., 1988;

Pandolfi et al., 1988; Pandolfi and Bonaco- scia, 1991: Boldreghini and Pwdolfi. 1991‘) and birds (e. g. Meschini et al., 1981: Moc- ci Demartis and Melis. 1985; Mainardi, 1988). However, it was suggested by Mac- donald et al. (19x0) that the appearance of waste in the diet of certain species most pro- bably depends 011 the lack oT natural food, such as prey for carnivorous mammals. In- fact in the areas in which prey is more abun- dant the use of waste as food supply is rare.

From previous papers, it seems that exploi-

ting rubbish dumps has become a profitable

habit for certain species for two main rea-

sons: an intrinsic one, concerning the spe-

24 4. Martina and M. Gallarati

cies ecology, and an extrinric one. due to the lack of natural prey and the fact that feeding off human wasle is easy.

O B J E C TIVES

In the second hall of the seventies. the lea- ding rolc of rubbish dumps as l'ood sources for both wolves Cmis lupi,s and red foxes Ihlpes ~ x l p s was pointed out in studies in the Majella area (Macdonald et al., 1980).

Recently, the need to verify if the dumps were still visited by wild animals has arisen.

The present research was planned to inve- stigate the following topics:

1. list of the species which visit the dump;

2. seasonal variations in use of the dump;

3. dump use frcqucncy in the time range of the observations (from dawn to sunset).

S T l J D Y A R E A S

The rubbish dump observed in this sludy belongs to the administration of thc Village of Crinipo di Giove ( i n I'Aquila province) and is located in the south-western side of the Majella massif. The rubbish dump is partially fcnccd. Howcvcr this does not prevent animals froin entering it. 'Ihe dump

situated 2.5 km away from the village at an altitude of 1100 meters a.s.1..

MKI'EKIAL A N D MEI'HODS Diiwr ohsrnntioris

Monthly observations wcrc made inside the dump from September 1990 to Maj 1992. These were divided into three time lags (from 0 S : O O P.M. to 09:00 P.M.. from 09:OO P.M. to O1:00 A.M., from 0 1 : O O to O6:OO A.M.). The observa- tions were undertaken froin a car which had dark windows. A pair ol'binoculars (8x56) and a light intcnsificr for night vision (5,) was used. In cx- treine conditions (cloudy arid moon-less nights),

ii halogen lamp (100 watt) w a s neces\:u-y. Due t o thc long tinic lag, thc low night tcmpcratiire~ and theextend use of the optical instruments, 20 ini- nutes of continuous observation were alternated with 20 minutes of rest. to reduce imprecisions in observation caused by weariness.

The complete repor1 consists of 300 twenty-mi- nutc continuous obscrvation intervals that add up to a total of 133 hours (76 in 1 990-9 I , 56 i n 9 1

92). The sampling method used was crtl lihirrmi (Lovari. 1980; Martin and Bateson, 1990).

E/ahor~crtio/i

A report was carried out to see if any species had favourile times for visiling the dump. To do this an analysis method that allows to obtain the asymmetry index

was done according to Le- ti (1983). The index was obtained by gathering the siphtings of every single species in six time interv a la (OS : 00-07 : 00 P. M . , 07 :00-00 : 00 P. M

, U3:OO A . M . . 03:UO-0S:OO A.M.). After having calculatcd the median value of the series which represents the sightiiigs distribution, we calculu- ted the dispersion index D :

09:OO-I 1100 P.M., 11:00 P.M.-OI:O0A.M.. 01:00-

where F,, is the accumulated relative frequency related to the h"' modality. Thc asyniinctry index a i s obtained by the forrnula:

where D i slantls for the diclributiori index coii- ccrning the first 1712 terms ( n cvcn) or the first ( / I

+ 1112 terms ( n oddj and U , stands for distribu- tion dispersion index concerning the last t f / 2 t e r m ( n even) or the last ( 1 1 + I)/? terms

odd).

If D,, = D , the result is symmelrical, i f D,, > /I, it is positively asynimctric. if D, i D,, it is ncga- tively asyrnrnetric. Moreover if U , = 0 it follows that rr = I , which is maximum positive asymme- try. If = 0 it follows that

= - 1 . which is maximum negative asymmetry.

R E S UL TS AND DI SC U SS I O N

The data on which we workcd o n concerned

only animal sightings of which identifica-

tion was 100% certain. We didn't consider thc sightings where the shape of tlie obser- ved animal was not clear or where we could only distinguish its t q i e m j i Irrc.itfunr's re- tlex. Moreover we could only cover W k of the dump's area from the car. so logically the effective level of animal presence is pro- bably higher than the one recorded during tlie study.

Ohsei-\wi ,spc.cie.s

In the two-year period of study, I 1 I animal presences were recordcd (65 in 1990-9 1 and 46 in 1991-93).

The following species were observed: the red fox I,'zrIpes \.r/lpcs (39%) of the sigli- tings), the domestic cat Felis [.silivsIri.s/ U -

t u s (27%), the dog Ctriris [ l u p s / fimiliai-i.~

(20%~), the wolf C m i s / u p s ( 14%).

The absence of characteristic markings on the wolvea and red foxcs meant that the identification ol' a singlc individual of the bame specics was impossible. l n Tab. 1 the sightings pcrceiitage related to the number of individuals seen at the same time during a single observation is reported. Most of the sightings relate to a single individual in the case of the cat, the wolf and the red [ox.

Dogs for the most part canie in groups from two to six individuals.

l ~ O l l / h / ~ pIP.SPllc'e tWF7u'

It waa impossiblc to carry out an in-depth statistical analysis of seasonal variations in dump use for cach species. This was becau- sc the numbei- of sightings was insufficient

and the study period was very limited be- cause the dump was closed down in June 1992 so thc rcscarch couldn't continue. As a result wc have limited ourcelves to simply reporting the results in graphic form and we have hypothesized on some trends.

The trend in nionthly presences (Fig. 1) du- ring the first year is different from the one obtained in the same months of the second year. This difference is probably due to the changes i n waste supplies which depended on the random and discontinuous garbage removal undertaken by the village admini- stration (the removal was donc by burying the waste with a bulldozer). The burying was done constantly only during March, April and May I99 1 : the lack of waste sup- plies could explain the almoqt total absence of animals during this period.

The observations during September, Octo- ber and November 1991 show a similar trend of presences for the four specics.

However this similarity was not Twnd in the same period of the following ycar. The hi- ghest attendancc absolute maximum (relati-

\'e maximum i n the dog) during the entire period o f study was recorded in October. A number of different reasons could explain lhese results. During autumn microinam- mals represent an important food source for the red fox (Pandolfi and Bonacoscia. 1991) and the dump is a favourite settling area Tor some rodents. This was found to be surc in particular for Xaltiis sp. (pers. obs.) so, coii- sequently. this high densily could be a further attraclivc factor for predators.

Table 1

Sightings percentage i n relation to the numher of the individuals at the same time visi- ble to the observer.

1000-1002 I ind. 2 ind. 3 ind. 4 irid. 5 ind. h ind. 'l'ntal

11

u

h r s

of bighting\

26 A. Martiria and M. Gallarati

Canis

vF====

Y 2 1 0

Vulpes vulpes

8 , 0

6 5 Y 4 3 2 1 0

Felis [silvestris] catus

7 6 5 Y 4 3 2 1 0

Canis [lopus] familiaris

S O N D G F M A M G L A S O N D G F M 4 M

MONTHS

Fipuie 1

Obseived species prewnw (monthly trend) (September 1990 - Ma) 1992)

In winter. snowfalls covered the garbage heaps and the low night temperatures froze the mantle. so making any attempt by the animals to dig for food very difficult.

Furthermore. because of the snow, the gar- bage discharge was not performed daily, but only al'tcr the streets had been cleared for thc truck to move. The presence or absence of animals could have depended on the bad weather conditions that limited the waste

supplies to those disposed in betwccn two snowfalls. However the red fox showed an attendance peak i n January '92. Its atten- dance peak shift to January could be becau- se of a hole up in the dispersion of red foxes in the area due to a delay in the reproducti- ve cycle of that year. In fact, as Storni et al.

report ( i n Boitani and Venditti, 1988), the beginning of the young red foxes dispersion period could depend on the cub birthdate and on their growing and maturity phases.

The increase of the human population du- ring the tourist season and the consequent increase of daily waste co~ild be the main factor that attracted red foxes, wolves and cats to the dump in summer.

A comprehensive comparison of the graphics shows that the red fox visited the dump with the most continuity over the whole 21 month period. The wolf and the cat visited the dump for shorter periods and the dog was the more irregular of all. The red fox's wide feeding range could account for its frequent visits to the dump.

The howls. the marks on the snow and other factors revealed us the presence of a pack of wolvcs (2-6 individuals probably) in the south-western area of the Majella during the period of study. Boitani (1982) reports the wolr as strongly dependent on waste in A ~ I - u z ~ o . On the other hand a scarse depen- dence was recorded by Patalano (1991) in the Abruzzo National Park, and Matteucci (1992) reported that wolf feeding habits in the northern Apennines area are totally orientated towards wild ungulates. We ob- served single individuals more frequently (in 6 2 3 % of the sightings) in the dump.

The sightings of the cat resulted in being the same individuals (2). In a Swedish popula- tion of a rural free roaming domestic cats.

Liborg (1980) classified them as house cats

when they regularly fed in onc or several

household and he classilied cats that didn't

have such connections a s being feral. The

feral cats usually had a larger home range

(2-4 km) than the house cats. Taking into

consideration the long distance between the

Canis lopos a 0,38

Y :Io&> ^{2 ,}

0

17 19 21 23 01 03 05 Vulpes volpes a = - 0,52

20 T 17

17 19 21 23 01 03 05

Felis [silvestriJ catus a = 0,72

8 6 y 4

2 0

17 19 21 23 01 03 05 Canis [lupus] familiaris a = 0

17 19 21 23 01 03 05 TIME INTERVALS

Figure 2 - Number 01 yecies observations in rc- lation to tiinc lags. Besides the species scientific name the asymmetry index value “a” is repor- ted; the mean value is shown by the vertically dashed line.

dump and the nearest village we can proba- bly assume that the cats we observed were ferals.

The dog was observed many times even du- ring daytime and probably visited the dump for the whole 24 hours. We can concludc therefore that it is far more dependent on waste food than the results could lead us to think.

A,\ynznzeti~y ctrict1j.ri.v

The values obtained i n the asymmetry analysis application were as follows: the wolf a = +0,3X: the red fox rx = -032; the domestic cat a = + 0,12; the dog n = 0. The sightings number per species in relation to tlie time intervals and the related asymme- try index is shown in Fig. 2.

As far as the wolf is concerned two peaks o r maximum attendancc wcrc rccordcd in two intervals. 09:OO- 1 1 :00 P.M. and 03:OO-O5:OO A . M . : despite the fact the positive value ob- tained for the asymmetry index ( a = 0,3X) iiidicates a favourite visiting time interval between 07:OO- 11 :00 P.M. The asymmetry index was found to be positive for the cat ^{( L I}

= 0.12) and the favourite visiting time in- terval was in the evening hours (0S:OO- 1O:OO P.M.. The red fox’s asymmetry index was found to be negative ( a = - 0.52): so, conscqucntly it follows that the favourite vi- siting time has to be restricted to the late ni- ght hours (02:OO-0S:OO A.M.). Plus, tlie red fox’s activity reported in Cavallini & Lova- ri (1994) is very intense late at night ( 1200 P. M. - 02:OO A.M.), but its maximum was between 08:00-10:00 P.M.

We obtained an almost pcrfcct symmetry only for thc dog ^{( U} = 0), which suggest the visits bctwccn 0S:OO- 1O:OO P.M. were as much appreciated as those between 10:00 P.M.-03:00 A.M.. The absence of a favouri- te visiting night-time is probably due to the possibility of frequenting the dump in the day-time too.

Different species were sighted in the same

time intervals but, we cannot ascerlain i f the

presence of one of thcse had an intluence on

28 4. hlartina and hl. Gallarati

the presence (sending awlay or approach) of other species. We can only rcport single epi- sodes that could lead to a wide range of con- clusions. In fact these suppositions could be a good starting point for new deepened re- search:

October 12. 1991

OR40 A.M.

"A wolf, a cat and a red fox were present at the sanie time. Although each one was aware of the others no physical interaction tooh place". A similar event is also reported in Boitani

( 1988).

November 20. I99 I

1 :20 A.M. (videotaped sequence) '' A red fox and two domestic cats are present at the same time: the three ani- inals are moving together (the fox procee- ding at a jog-trot while scavenging and the cats moving step by step). The red fox is re- peatedly driven away by the cats, perhaps because it is too close".

February 2, 1992

I0:40 P.M. '' A little dog pack is present in the dump: 2 adult males.

1 adult female and three puppies. A wolf is a little farther away inside the dump. The adult dogs, barking and running. attack the wolf which runs away downhill chased by the two males whose barking dies away. The female remains in the dump barking in the direction of the pursuit".

A CKNOWLEDGEMENT

We wish to remernberthe late ^Paolo R a r r a s o who conceived this research arid who above all was a precious and invaluable friend,

We would like to thank the National Forest Corp.

in particular Di Croce, for having approvcd the use of the Valle dell'Orfento Katural Rcserve's wuctures. and thc Caramanico-bis command pcrsoncl for thcir valid help.

Wc are also grateful to R. Sil\,aggi and W. M.

Santoleri for their help on the field, to E. Rrurio and V. Penteriani for their advice during the da- ta gathering and to S. Quistelli for her contribu- tion in the data anal . We are particularly gra- teful to Sandro 1,ovari for hi5 precious advicc and

fur his valuablc criticism during the compiling of thi5 work.

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