EURING Newsletter - Volume 2, December 1998

EURING PROJECTS

THE EURING SWALLOW PROJECT:
RESULTS FROM THE FIRST PILOT YEAR

By Fernando Spina

ITALIAN RINGING CENTRE, ISTITUTO NAZIONALE PER LA FAUNA SELVATICA, VIA CA' FORNACETTA, 9 -I-40064 OZZANO EMILIA (BO), ITALY (E-mail: infsmigr@iperbole.bologna.it)

The EURING Swallow Project has been launched in 1997 as a first pilot year. The project has stimulated a large interest among European ringers, and intense research activities have been carried on. Being an experimental phase, this first year has allowed checking field methods and protocols, and many colleagues have offered their comments and suggestions for further improving the field manual. This has been revised and widely circulated by Lukas Jenni. A brief newsletter has been produced, and its contents will appear in the section below. Brief national reports on the activities in Finland, Slovenia and Italy will also be presented.

In a first pilot year which has been quite a success already, a very intense activity has taken place in many European countries, where large numbers of birds have been ringed, following our detailed field protocols. This brief report offers a general overview of the geographical coverage obtained during 1997, of the kind of data collected by the different schemes, and of the coverage for 1998.

Geographical coverage 1997: despite being a pilot year, and despite also the fact that the very detailed field manual was distributed fairly late with respect to the onset of the breeding season, the project got a very good geographical coverage.

A total of 17 different countries (Fig. 1, Tab. 1) could join the project, with a very interesting geographical scatter, offering a fairly complete ‘transect’ across western and central Europe.

Tab. 1 - List of the 17 countries which joined the project with some brief results from the first year of activity.
A total of 115,855 Swallows have been ringed.

Data gathered in 1997: among the active countries, 10 carried on ringing activities both during the breeding season and the pre-migratory phase (Fig. 2), while ringing was concentrated during the breeding season in 3 countries, and during the roost period in 4 more countries.

An estimated number of over 300 ringers took part into the field activities, positively confirming the large interest stimulated by this project in Europe.

From the data available so far, a grand total of 115,855 swallows have been ringed (Tab. 1), quite an impressive figure for a starting year, with a huge potential of information.

Breeding biology: it is particularly interesting that over 30,000 birds have been ringed at the colonies. Ringing during the breeding season is particularly important within this project, as it will unable to investigate aspects related to geographical variability in reproductive parameters, natal dispersal, migratory routes and winter quarters of birds of known origin. This large coverage of colonies will also offer possibilities to stimulate some of the most interesting aspects related to the breeding biology part of the project, as inter- and intra-population genetic variability.

Pre-migratory phase: the pre-migratory strategies adopted by the different swallow populations are another focal aspect for the project. In 1997 approximately 80 different roosts were covered, many of them during the whole season, and on a regular weekly basis, as recommended by the protocols.

Over 85,000 swallows were ringed and the data have already partly been analysed. Duration of the roost phase, accumulation of fat reserves and physical conditions of birds leaving on their autumn migration are all aspects which have been investigated. Such large numbers of ringed birds will also help defining the migratory routes followed by the different geographical populations of swallows across Europe and towards Africa.

Given the fact that such an intense effort in swallow ringing had never been produced, significant numbers of recoveries from the winter quarters are to be expected, which will contribute in better describing the distribution of the main roosts in Africa, as a key issue also for swallow conservation.

Future prospects: the first results originating from the analyses of data collected in 1997 will undoubtedly stimulate further interest in swallow studies in Europe and beyond. In fact, there seems to be at present a positive interest both from the U.S. and Japan to join the project; the Japanese Ringing Scheme in particular is actively working on the swallow already since few years.

The EURING Swallow Project at the XXII IOC: a full symposium has been devoted to our swallow project during the International Ornithological Congress in Durban (South Africa - August 1998), convened by Prof. Dr. Arie van Noordwijk (The Netherlands) and Dr. Terry Oatley (South Africa). The symposium, titled ‘The involvement of amateur ringers in population studies: The EURING Swallow Project’, took place on August 17th 1998.

Five talks were offered during the meeting, which are listed here, followed by a brief abstract:

1. The EURING swallow project: Amateur ringers in population studies, by Arie van Noordwijk.

The Dutch Swallow project was started as a pilot and demonstration project for a new type of ringing concentrating on breeding populations of single species and documenting variation in breeding, survival and dispersal as main questions. In the later extension into a EURING project, the pre-migratory phase and the wintering biology have been included. Over the next decade, the enormous potential work force of amateur ringers could lead to a new scale of studying the population biology of species in which studying variation among individuals within populations is combined with small and large-scale geographical comparisons.

2. The EURING swallow project: a ringer's perspective, by Bennie van den Brink & Arie van Noordwijk

During the last decades the population of the Barn Swallow Hirundo rustica has decreased in their European breeding grounds. This decrease varies among regions and countries. To study the causes, the Dutch Ringing Scheme initiated a research program in which amateur ringers are involved. The aims are to collect data on annual production of young, dispersal of offspring, site fidelity and the number of breeding pairs. Regions were chosen to include combinations of three contrasts: rich versus poor soil fertility, wet versus dry and large scale versus small scale agricultural land use. In each region we follow 50 to 150 pairs. There is substantial variation in fledgling production per year and per region, dispersal of first breeders, site fidelity of adult birds in later years. This project involves many amateur ringers in a single species study and thus combines the large data-gathering capacity of amateurs with professional design and analyses.

3. Fat accumulation in pre-migratory roosting Barn Swallows in Europe, by Andrea Pilastro & Fernando Spina.

The pre-migratory roosting behaviour of the Barn Swallow allows to study the variation of fat accumulation dynamics during the season and between different geographical areas. Previous analyses of body moult progress and fat accumulation across Italy suggest that a fast fat accumulation starts when body moult is completed. Daily body mass increase is in the range of those reported for other trans-Saharan passerine migrants, suggesting the potential for Swallows to cross the Mediterranean and Sahara without substantial refuelling.

Out of the over 85,000 swallows ringed in 17 European countries during the pilot year of the EURING Swallow Project, data from 5 European Countries were available by April 1998. A total of 43,000 swallows ringed during 720 capture sessions were taken into account. Analysis of body mass variation over a wide geographical range (range=37N to 62N; 6W to 26E) suggest that migration strategies may differ between western populations (namely UK and Spain) and those passing through Central and Eastern Europe (Finland, Switzerland and Italy). In particular, an increase in body mass is observed in all five countries from the end of August, starting almost simultaneously at all latitudes.

In the second half of September adult Swallows with body mass over 24g. were recorded in UK, Switzerland, Spain and Italy, with the highest frequency observed in Italy south of 43°N. Apparently, swallows migrating through Italy accumulated more fat than those following the Iberian Peninsula, which could be very interestingly related to the different distances to overcome across ecological barriers.

4. Barn Swallows in Africa: Effects of rainfall on body condition and speed of moult, by Tom van der Have & Bennie van der Brink.

The long-term decrease in Barn Swallow numbers has been attributed to various factors in the breeding and non-breeding areas. Effects of rainfall on variability in body condition and rate of moult were investigated in Botswana (1993 to 1995) and Ghana (1996/97) in December to January. Rainfall varied dramatically between years in Botswana, resulting in reduced roosting habitat in 1993/94 and 1994/95, and dry periods in 1992/93 and 1994/95.

Body mass was high in 1992/93, but much lower in the other years. In 1992/93 and 1994/95 body mass decreased when rainfall ceased, and increased gradually after rainfall, which triggered termite flights. Rate of moult between years correlated with average body mass. In Ghana significant differences were found in moult index, wing length and weight between northern and southern locations and with the non-breeding population in Botswana.

It is concluded that body mass and speed of moult in Barn Swallows wintering in Botswana is the result of the interaction between rainfall, affecting food availability, and the amount of available roosting habitat, determining flight distance to foraging areas and bird density

5. Potential and problems of large scale involvement of amateurs, by Terry Oatley & Arie van Noordwijk.

The example of the EURING Swallow Project has been used to demonstrate the potential of the interactions between amateurs and professionals in large-scale ornithological studies. The two main areas in which there are substantial differences between amateurs and professionals are project design and data-analysis. Many amateurs enjoy the interactions with professionals and are willing to provide very many hours of first-class fieldwork. In the past, there was often a serious bottleneck in data-entry in the computer, but with the spread of micro-computers most amateurs can enter data in the computer and send them in on electronic media.

Most amateurs are rather reluctant to participate in any sort of experimental manipulation, and moreover legal requirements in most countries would create large problems in doing so. Thus, projects that require large amounts of relatively simple data are ideal for the involvement of amateurs. In the Dutch example, the provision of a computer programme that enables the ringers to produce annual reports of their own study areas proved to be of crucial importance, which in turn is an important item in the relation with the farmers on whose farms they work.

The symposium has been a very important initiative, introducing both large-scale ringing projects and EURING to the wide audience of the I.O.C. The contributions offered during the symposium give an overview of the different aspects of the annual cycle of a long-distance migrant which can be covered through a widespread network of ringers working on common protocols based on standardised field methods.

The wider coverage which we’re going to get in 1998 will further contribute to the analysis of the geographical variability in demographic parameters and migration strategies of this widespread species, which is showing negative population trends in several European countries.

Many contacts originated with African ringers thanks to the symposium, and several roosts will be covered during this winter; these complementary data from the African quarters will offer the unique possibility of monitoring the whole annual cycle of our Swallows!

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