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PROJECT REPORT

Praying for the “White Dove”: How do wildlife populations perceive massive human

pilgrimages?

Julio Blas Garcíaa

aEstación Biológica de Doñana, CSIC, Americo Vespucio s/n, 41092 Sevilla, Spain

Cover photo: a white stork chick (Ciconia ciconia) in one of the nests selected for this study in the Doñana MaB Biosphere Reserve (upper picture). The field house in the background is the "Palacio del Coto del Rey", one of the major stopover camp sites for pilgrims. A religious pilgrimage (lower picture) is held in Doñana once a year in honor of the Virgin of El Rocio, also known as the “White Dove”. The biosphere reserve is then crossed by thousands of vehicles and hundreds of thousands people in their way to the town of El Rocio. Such a massive human pilgrimage can potentially generate conflict between the maintenance of cultural traditions and the conservation of biodiversity. Photo credits: Julio Blas

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INTRODUCTION

One of the major challenges for conservation biologists is reconciling the

conflicts between human activities and the preservation of biodiversity. As human

population grows, anthropogenic pressures expand and pervade all ecosystems at a

global scale (Vitousek 1997; Ellis & Ramankutty 2008) affecting not only transformed

lands, but also many areas around and within well preserved natural environments

(e.g. Spellerberg 1998; Velando 2011). Biosphere Reserves are not exempt from

anthropogenic activities and in fact, a major reason for their foundation is allowing a

sustainable maintenance of cultural and historical traditions (Madrid Action Plan for

Biosphere Reserves 2008-2013). The extinction of particular traditions is therefore a

reason of concern (e.g. Dasmann 1991; Naveh 1998). But local and initially low-impact

cultural activities can also grow in popularity to become massive social events,

jeopardizing a fine balance between the well-being of both human populations and

the environment.

Figure 1. The Doñana MaB Biosphere Reserve. Location of the Biosphere Reserve, indicating the legal limits of the protected land (National Park and Natural Park), main towns and major routes of pilgrimage through the reserve.

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Such circumstance could be currently taking place in the Doñana National Park,

Spain (Figure 1), a Biosphere Reserve and UNESCO World Heritage Site considered one

of the most important wetlands of the world (Aritio 2001; Garcia Novo 2006). Here

some 300 species of vertebrates (including 6 million migratory birds) coexist with

traditional human activities such as open-range cattle-raising, agriculture, shell-fishing

and agro-environmental tourism (Ruiz de Larramendi 2002; Garcia Novo 2006).

However, during the last decades Doñana has also become an increasingly popular

destination for religious pilgrimages. The Catholic tradition recounts a Virgin appearing

in the village of El Rocío (northern tip of the Park, current population: 750 inhabitants)

in the thirteenth century, quickly becoming a symbol of devotion for the local

communities (Mountfort 1958; Martinez Moreno 1997).

Figure 2. Pilgrims crossing the Doñana Biosphere Reserve. Despite the picture of people walking on their feet beside traditional carriages pulled by livestock (upper three pictures) constitutes the "typical" image of the "El Rocio" (the "White Dove" pilgrimage), this procession involves thousands of trucks, all-terrain cars, carriages and wagons pulled by motor vehicles (lower three pictures). Despite the existence of such non-traditional ways of crossing the reserve is often neglected, it likely exerts negative impacts on the natural resources, and the ease of access that it entails probably explains the dramatic increase in popularity experienced by this pilgrimage during the last decades. Photo credits: Julio Blas.

A pilgrimage is held once a year in honor of the Virgin of El Rocio (the “Romería

de El Rocio”; Figure 2), also known as the “White Dove” (“La Blanca Paloma”). The

originally modest procession has become so popular in this globalized world, that

nowadays the White Dove constitutes one of Spain’s holiest images and the

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pilgrimages are described as a “festival of postmodernity” (Martinez Moreno 1997).

Nowadays the White Dove pilgrimage attracts over one million people at a time (e.g.

1,300,000 persons in 2011), making the modest town of El Rocío the third largest city

of Spain for one week (http://www.visithuelva.com/travelguides/provincia_elrocio-

es.htm). Parades of trucks, all-terrain vehicles, carriages, wagons, horses and hundreds

of thousands of faithful people walking and riding on horseback and travelling for days

through the Park to reach the White Dove.

Figure 3. White Storks. After performing regular surveys in search of nests of several avian species, white storks (Ciconia ciconia) were selected as study models due to the presence of numerous nests beside a major route of pilgrimage. The aggregation of nests within a colony allowed the simultaneous quantification of behavior in a large sample of individuals while concurrently assessing the temporal dynamics of human presence in the same area. Photo credits: Julio Blas.

This spectacular tradition involving men, women, families, the elderly and kids

(Figure 2) takes place right at the height of the breeding season of most wildlife

species inhabiting the National Park, many of which (such as the Iberian Lynx Lynx

pardinus or the Spanish Imperial Eagle Aquila adalberti ) are critically endangered.

Such outstanding spatial and temporal coincidence of humans and wildlife generates a

potential conflict between the preservation and sustainable use of unique biological

resources, and the maintenance of strongly rooted cultural and historical traditions

which are no longer restricted to local communities. At the same time, these

peculiarities offer a unique opportunity to understand how wildlife populations

perceive such massive, but short-term human congregations, and whether they have

evolved biological strategies to overcome anthropogenic stress. Therefore, the main

research goal of this project was to assess whether a massive, but short-term

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presence of humans in the national park during the El Rocio pilgrimage affects the

behavior and breeding performance of wild birds. Understanding such mechanisms

may allow researchers and wildlife managers to develop better conservation

strategies aimed at reconciling conflicts and maximizing sustainable uses of the Earth's

biological, cultural, and historical resources.

ACTIVITIES PERFORMED AND PRELIMINARY RESULTS

Between March 1st and May 15th 2014 (several weeks ahead of the

celebration of the El Rocío pilgrimage in 2014) regular surveys were conducted along

the park routes traditionally used by the pilgrims, with the aim of locating nests of

wild avian species. In particular, our search was focused on colonial or semicolonial

breeding species including Black kites (Milvus migrans), Bee-eaters (Merops apiaster)

and White storks (Ciconia ciconia) because clumped nest aggregations would allow the

simultaneous quantification of wildlife behavior in a large sample of individuals while

concurrently assessing the amount of human presence during the pilgrimage.

Figure 4. The study area. The focal colony of white storks was located beside a field house known as "Palacio del Coto del Rey", which is once a year a major stopover and camp site for thousands of pilgrims in their route towards the town of El Rocio. The stork nests are therefore exposed to massive human presence during a short period (a few days per year). Automatic vehicle counters were placed along the dirt roads used by pilgrims, with the aim of assessing the spatiotemporal dynamics of human presence, potentially affecting the behavior and performance of white storks.

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This initial search resulted in the location of a colony of white storks (Figure 3)

near the "Palacio del Coto del Rey", a field house in the northern areas of the Doñana

Mab biosphere reserve (Figure 1). This field house is a major stopover site for pilgrims,

who traditionally parade along the front side of the house in their way towards the

town of El Rocío. The colony of white storks was composed of c.a. 40 active nests on a

group of trees located 30-100m from a major pilgrimage transit way, and c.a. 300

meters away from a camp site that is only used during this traditional event (Figure 4).

The reproductive phenology of the white storks in Doñana allowed us anticipating that

the adults in the study nests would be brooding nestlings during the estimated dates

of pilgrims passage.

In order to quantify temporal changes in human presence associated to the El

Rocio pilgrimage, we placed automatic vehicle counters (Figure 5; TRAFx Vehicle

Counter Generation III; http://www.trafx.net) beside the two dirt roads allowing

access to the study site.

Figure 5. Automatic vehicle counters. Automatic vehicle counters were placed in the dirt roads passing beside the study colony of white storks. The commercial magnetometers (TRAFx Vehicle Counter Generation III), and allow registering all vehicles passing within a 6m radius. The counters were buried in the ground to prevent avoidance of the sampling point by drivers. Photo credits: Julio Blas.

The automatic counters were buried in the ground 30 cm deep (to prevent

avoidance of the sampling point by pilgrims) and were active between May 30th and

June 13th, 2014. This period allowed us assessing the amount of human presence

affecting the study area before the start of the pilgrimage (i.e. between May 30th and

June 3rd) as well as during the pilgrimage towards the town of El Rocio (between June

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4th and June 8th), during the return of pilgrims from El Rocio (between June 9th and

10th) and after the pilgrimage ended (between June 11th and June 15th). In order to

assess the accuracy of automatic vehicle counters, we performed concurrent visual

censuses of passing vehicles during seven (N=7) 1-hour long intervals on June 4th.

In order to assess changes in avian behavior associated to human presence, a

few days before the start of the pilgrimage (on May 28th and 29th) we placed 16

compact, camouflage painted digital photo traps in a sample of 16 nests containing

storks nestlings (Figure 6).

Figure 6. Installing photo traps. After accessing the focal study nests, we placed compact, camouflage painted digital photo traps (red circles in left and central picture). The cameras were soon accepted by adult and nestling storks, allowing us to monitor behavior and subsequently relate changes in parental care to the temporal changes in human presence during the pilgrimage. The stork nestlings were banded with white plastic rings containing unique alphanumeric codes (right picture).

The cameras were activated by an automatic movement sensor set to capture

two photographs per movement during daylight hours (i.e. between 6:30 and 22:00h)

to maximize battery life. Nests were accessed with a motorized elevator (Haulotte

26M) and the storks chicks were banded with a white plastic ring coded with black

alphanumeric characters that allowed subsequent identification in the photographs.

The nestlings were also measured and weighted with the aim of estimating their age

and body condition. Nests were accessed a second time on June 3rd to collect the

photographic information recorded before the onset of the pilgrimage (i.e.

photographs taken between May 30th and June 2nd), replace the camera batteries

and the memory cards, and a third and last time on June 7th to collect the information

recorded during the main passage of pilgrims towards El Rocio (i.e. photographs taken

between June 3rd and June 6th). During the latter visit, nestlings were measured and

weighted a second time, mortality and predation events were recorded and the

photographic camera traps were removed from the nests.

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Figure 7. Schematic chronogram of the pilgrimage and associated field activities. (A) Calendar showing the date of celebration of the "White Dove" procession in the town of El Rocío (on June 8th 2014, highlighted in red), and the main transit periods of pilgrims through the Doñana MaB Biosphere reserve (in red: June 4th-7th comprise movements towards the town before the celebration, and June 9th-10th comprise movements from the town, after the celebration). (B) Dates when the automatic vehicle counters were recording the amount of motor transit beside the study colonies. Numbers in grey cells show preliminary data collected from one of the vehicle counters. (C) Dates when the photographic camera traps were recording storks´ behavior in the focal nests. Numbers in pink cells indicate the amount of pictures collected before and during the passage of pilgrims by the study area. (D) Dates when the stork nestlings were banded and the biometric information was recorded.

Figure 7 presents a schematic chronogram of the field activities performed

during the course of this research project, and some preliminary information including

estimates of the vehicles recorded by one of the vehicle counters, and the number of

pictures collected by camera traps. A visual inspection of the traffic data (Figure 7-B)

allows understanding the dramatic changes in human presence experienced by the

local storks. Daily traffic levels were very low before and after the pilgrimage (mean

11,1 vehicles/day; range 1-19), suggesting that the colony of storks is located in a

quiet, natural environment with negligible human presence. However, during the six

days of pilgrims passage, average traffic levels increased to 763,5 vehicles/day (range

354-1276). The actual impact of motorized traffic should be considerably higher

during the pilgrimage, as the preliminary data presented here only contains

information from one vehicle counter (data from the other counters is currently being

extracted for analyses). Furthermore, the information provided by automatic vehicle

counters only registered motorized entries to the study area (traffic regulations only

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allow one-way movements towards El Rocío), but the perturbation exerted by humans

should also consider the presence of walking people and horse riders, as well as the

permanence of all (vehicles, people and animals) in the camp site. These preliminary

numbers provide an initial approximation to the dramatic changes in human presence

that local storks experience during a few days.

Figure 8. Photographic sequence of a feeding event. (1) Upon arrival of an adult to the nest, the chicks (A and B in the example) perform a stereotypical begging display lowering their heads towards the centre of the nest and moving their wings rhythmically. (2) The adult responds elongating the neck, lowering the head and placing the open beak near the centre of the nest ground, with a visible red pouch. Nestlings may touch the adult beak during the begging display to stimulate regurgitation. (3) The adult regurgitates food on the ground of the nest. (4) Nestlings collect regurgitated food from the ground of the nest (nestlings do not feed directly from the beak of the adult). In the enlarged photographic insert, chick A is ingesting an American crayfish (Procambarus clarkii).

The information collected by the photographic cameras should allow us to

assess whether the focal storks modified their behavior in response to the pilgrimage.

During a four-day period prior to the pilgrimage, the photographic cameras collected

130911 pictures. Furthermore, 96007 additional pictures were collected during the

first three-days of pilgrims passage beside the focal stork colony (Figure 7-C). The vast

amount of information contained in this sample of over 220000 photographs is

currently being processed with the aim of extracting the number of feeding events

recorded each day in each of the focal nests. Feeding events are being identified in the

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collected pictures according to the stereotypical behavior displayed by adult and

nestling storks. As it is illustrated in Figure 8, the begging display of stork chicks

involves lowering the head towards the centre of the nest and moving the wings

rhythmically. If the adult responds to chick begging, we typically visualize it elongating

the neck, lowering the head and placing the open beak near the centre of the nest

ground with a visible red pouch. Feeding events are confirmed if the photographs

capture the adult regurgitating food on the ground of nest, and/or a nestling is

visualized ingesting food.

Figure 9. Photographic sequence of a showering event. Sometimes adults regurgitate water on top of their nestlings, allowing them drinking (straight from the beak of the adult or intercepting the stream of water) and wetting their plumage to cool them down (elevated temperatures are common in the study area).

The current screening of the photographs is also allowing an assessment of the

number of showers and drinking events recorded in the focal nests during the study

period (Figure 9). Adult storks provide water to nestlings for both drinking and wetting

their plumage, and this behavior also constitutes a type of parental care. In the

coming months, once the complete set of pictures has been visualized we will be able

to assess whether white stork in Doñana increase, decrease or maintain a similar level

of parental care in response to the massive presence of humans during the pilgrimage

towards El Rocio.

ACKNOWLEDGEMENTS

I thank Fernando Torres, Sebastián Palacios (Basti) and Sonia Cabezas for their

invaluable help to this project (Figure 10), specially for their contribution during field

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work activities and implementing the screening of the collected photographs. Javier

Chicano (Kiko), Francisco Hernández-Fernández and Alberto Herrero provided

technical support during field work (Figure 10) and allowed access to the stork nests.

Fabrizio Sergio, Francisco Carro, Eloy Revilla and Marcello D´Amico kindly provided

field materials and expertise. The staff of the Doñana National Park provided permits

to perform this research and information related to the pilgrimage. Part of this study

was funded by research project CGL2012-32544 of the Spanish Ministry of Economy

and Competitiveness and FEDER funds, and project 511/2012 of the Spanish Ministry

of Agriculture, Food and the Environment (Autonomous Organism of National Parks).

Julio Blas was supported by a Ramón y Cajal contract from the CSIC.

Figure 10. Study contributors. Some photos taken during the course of this study. (1) From left to right: Julio Blas and Sebastián Palacios (Basti) installing a photographic camera beside a nest of white storks containing two nestlings (visible in the lower right corner). (2) From left to right: Julio Blas, Fernando Torres and Sebastián Palacios (Basti) doing field work in Doñana. (3) From left to right: Julio Blas, Francisco Hernández, Sonia Cabezas, Fernando Torres, Sebastián Palacios (Basti), Francisco Chicano (Kiko) and Alberto Herrero at the Palacio del Coto del Rey (Doñana) during the course of this study.

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