brewood ringers

Results of a Ringing Expedition to the Parque Ambientale, Vilamoura, Portugal

20^th– 28^thSeptember 2011

Colin McShane (A);Fergus Henderson (A);Dave Clifton (A); Paul James (A); Chris Hughes (A); John Hodson (A); Lee Wells (A); Stuart Brown (A); Glynn Middleton(C); Shaun Micklewright (C) Dan Potter(C);Simon Davies(C) Simon Roberts (T); Moira Gough (T).

Introduction:

This expedition builds on the four very successful trips since 2007. One of the main reasons for visiting at this early date was to connect with some of the resident breeding birds as well as the first incoming migrants from further north. The intention was to complete a suite of results covering most of the prime autumn migration period—albeit over several calendar years. We now have results covering the whole of this period except 11^thto 13^thOctober.

This was the strongest ever team we have deployed in the Parque, in terms of numbers and ringing qualifications as well as in general ringing experience and experience of ringing at the Parque. Given this capacity, a further intention was to look to exploit some of the possibilities for ringing at sites which we have identified over previous visits, but which have not been fully exploited due to shortage of ringers. We also used sound systems much more effectively this year, and these, together with some extremely fine nets we were trialling, resulted in bigger than ever catches of some species, particularly hirundines.

The trip was a great success on almost every front. More birds were ringed, and a greater range of species handled than ever. The only disappointment was that most of the alternative ringing sites and activities proved to be less productive than hoped in numbers of birds ringed—although they did deliver some new species. However, the consensus was that experience from previous trips suggested that some of these sites could well be more productive at dates later in October.

Eleven new species were added to the overall species list, with a couple of unexpected surprises finding their way in to the nets and traps.

Our roost netting efforts were very disappointing. Although there were many more hirundines and wagtails than previous trips at later dates, we could not access suitable areas where they were roosting, and the Corn Buntings ( E.calandra) this year ( or this early?) failed to respond to the sound lures.

No sessions were lost due to adverse weather, the conditions being hot and settled during the whole period. However, bright sunshine and strong onshore winds on all but one day did reduce the catch from mid-mornings onwards. The absence of any periods of overnight rain, or heavy cloud cover almost certainly also reduced the number of birds ‘grounded’ on migration. Although the data show arrivals of certain species during the week, there were no obvious ‘falls’ of migrants.

Once again, our visit was well supported during the planning and implementation stages by our friends and contacts in Portugal; Nuno Grade, Vitor Encarnacao, Michael Armelin and Ana Luisa Quaresma, to whom we owe, as always, an immense debt of gratitude. The provision of a heavy duty undergrowth ‘strimmer’ by the Parque authorities, was particularly useful in quickly opening up traditional net rides as well as giving us access to previously inaccessible areas.

Methodology:  

Catching used on average 13 Japanese/Polish mist nets, set at fixed positions, practically identical to those set in previous years. The site is close to the observation hide and has become the main core area for the operation, and therefore provides some good comparative data.

Further nets were set on the northern edge of the marsh, which has been netted in all previous years except 2010. This area proved a little disappointing in terms of the numbers of birds caught, although the ‘quality’ was good. The main failing of this site compared to previous years was that it did not catch birds at roost time; especially Corn Buntings, which appeared to be flying high to the east presumably roosting much nearer the marina area.

An area of young pines between the beach and the river was netted on two occasions but apart from catching two new species, Jay ( G. glandarius) and Green Woodpecker ( P.viridis), it proved rather disappointing. However, reports from last year, during late October, suggested that this site may well be very good at that time, especially for finches, most of which had not arrived by late September.

Potentially one of the most exciting areas we opened up for ringing was an area of scrub and young olive bushes adjacent to the water treatment works. Although access is tricky, we feel that towards the end of our visit, we were beginning to get an insight into how valuable this area will be to visiting Sylvia warblers in particular later in the season. We would certainly hope to further develop this site in future visits.

 Extra nets were set in the fields to target species like wagtails, pipits, and hirundines and these proved immensely successful, as can be seen from the totals. Two evening trips to dazzle Red Necked Nightjars ( C. ruficollis) proved very successful and special efforts to catch raptors resulted in the great excitement of a Booted Eagle ( H.pennatus) and four Kestrels ( F.tinnunculus).

Nets were erected around 06.45 hrs each day, with sunrise around 07.15 hrs.  They were manned continuously and checked every 20 – 30 minutes.  Weather conditions were generally good and ringing carried on continuously, with nets being furled around 18.30 hrs.  When we were roost-netting, nets were taken down/furled at around 20.30 hrs. 

All birds were ringed using CEMPA rings and all were processed to record; age, sex, weight and maximum-chord wing length.  Migrant species were scored for fat, using the 5-point Euring scale.

Results:

(Species marked * were ringed for the first time in 2011)

Analysis:

As has been mentioned already, this was the 5^thsuch visit, and it was the earliest date for the visit. The intention throughout has been to construct a picture of migration through the Parque during the autumn passage period. As will be discussed later, this has been successfully achieved, but with some important shortcomings. Two further developments had a big impact on the species caught in 2011, whilst not detracting from the main purpose of the visit. These were first, the use of very fine monofilament nets and second the use of enhanced sound systems which, in conjunction with the new nets resulted in the large hirundine and wagtail catches.

NON-PASSERINES

Several new species were added to the list of those ringed, although all but one were not especially significant. Red-Necked Nightjars ( C.ruficollis) breed on the reserve, particularly in the more arid region near the original entrance and the sports stadium. On two evenings we tried dazzling these birds with some success. Six new birds were ringed and it will be interesting in future to see if any are re-trapped, and how late in the season this species will still be present on the reserve.

HIRUNDINES

There were many more swallows and martins around than in previous, later visits, although attempts at catching them at roost were disappointing. The birds appear to roost in the much wetter areas around the areas of open water and thus more difficult to net. However, it was very noticeable just after first light each morning that hundreds of hirundines would gather over the lagoons of the water treatment works just after emerging from their roosts. From then until late morning they were easily attracted to sound lures near our monofilament nets. As a result we far exceeded all previous totals, as well as adding House Martin ( D.urbicus) to the list. Red-Rumped Swallows (H.daurica) in particular were abundant and very susceptible to the lure, and as a result well over 300 were ringed.

CHATS, FLYCATCHERS and WARBLERS

This visit really emphasised the difference between Whinchat (S. rubetra) and Stonechat ( S. torquata). The former was caught in larger numbers than previous years, it being an earlier migrant, many individuals of which apparently move on south as October progresses. There was a clear influx on day 4 of this visit. Contrastingly, Stonechat is a late autumn bird in the area, many of which had not yet arrived compared to later visits.

The high number of Bluethroats (L.svecica) caught suggests an interesting pattern. Table/Graph 1 show how during late September/early October there is a distinct influx of this species, but that some of these birds continue, presumably into North Africa, resulting in fewer individuals spending the winter in the Parque. The pattern shown by Robins is opposite in that very few were apparent so early, suggesting that they arrive later, but more stay on to winter in the area.

Twice as many Pied Flycatchers (F.hypoleuca) were caught compared to previous years, and individuals were evident in the area on most days. We were surprised that we had not caught Spotted Flycatcher (M.striata) in previous years and wonder whether this is a comparatively rare species on passage this far west?

WARBLERS

The patterns shown by the 2 ‘resident’ warblers, Cetti’s ( C.cettia) and Sardinian (S.melanocephala), are complex and made more difficult to explain by an inherent problem with the regime we have used. The picture of migration over the month-long period has been compiled from five single week visits over five years. Year on year variation is obviously an important factor- but so are the catch rates within each week. For example, with resident species many more new birds are ringed early on in the week, with an apparent drop off as the week progresses. The main cause is obviously that most of the birds have been caught and some are becoming familiar with net sites. The net effect is to show bigger variations in 3-day totals than are actually the case. ( see later). However, there do appear to be larger numbers of these two species early in the autumn, and some individuals do appear to move away as winter approaches. A similar pattern is shown by Subalpine warbler (S.cantillans) even though actual numbers are smaller. This species is probably more of a typical migrant and there was a palpable influx on day 6 of this current visit.

Blackcap ( S.atricapilla) and Chiffchaff ( P.collybita) are typical winter visitors to the area. Both species show a dramatic increase in numbers caught later in October; the beginnings of the influx were apparent towards the end of this year’s visit. Willow warblers ( P.trochilus)on the other hand show a pattern typical of a passage visitor to the area with quite large numbers around during late September, (presumably from northern Europe) which quite quickly reduce to only a few individuals as late October arrives.

The pattern for Reed warbler ( A.scirpaceous) is one of the most complex to explain, presumably because the population in the Parque is both large and a composite of local breeding birds, and migrants from much further north. Controls of birds ringed in northern Europe support the latter point. Although many Reed warblers can still be found in late October (and some probably over-winter) there is a clear movement out of the reserve as autumn wears on. However, the fact that up to 10 new birds can be caught each day in late October shows just how many and how late this species does pass through the Algarve.

OTHERS

Catching wagtails and pipits is not easy, although monofilament nets make this a more viable possibility. However, we have not shown any definite patterns from ringing results to support the observations suggesting strong passage of these groups, especially in the surrounding fields which provide superb habitat for these birds.

In a similar fashion finch and bunting movements have not been studied as closely as they could. These groups tend to forage in surrounding areas and hence do not form a regular component of the catch. Nonetheless, observations do suggest strong patterns of movement in the area which would benefit from a more targeted approach.

Lastly, the appearance of a single immature Spectacled warbler (S.conspicillata) in a net in the middle of a weedy field is quite intriguing. We are not sure about the status of this species in the Algarve, but this was the first sighting of the species in the 5 years of our visits.

Discussion and Recommendations:

Data collection

The project has so far generated around 7,000 new birds ringed and around 20 controls of birds ringed elsewhere. This must represent a very good start in an area where previous ringing was sporadic. Indeed it can still be argued that this project has generated only sporadic results, and the shortcomings of this when trying to generate patterns has been pointed out earlier. Given that there appears to be no prospect of anyone operating at the Parque on a regular, systematic basis, we would like to suggest a way in which some of the current shortcomings at least can be put right. We have generated sufficient interest and expertise among our group of ringers to generate teams which could provide consistent coverage of the Parque during the main migration period—ie late September to late October. This would be the nearest we can offer to a constant effort site ( although it clearly is not that), and we have the agreed ‘support on the ground’ if this plan were to be accepted for 2012.

Habitat

One reason why we also would like to operate the above plan in 2012 is that changes to the habitat appear to be in an advanced state. It appears that much of the current weedy field areas are due to be converted into reed-beds as part of the plan to create a much larger marina area using up some of the present reserve open water areas. In the medium term this could have a very positive effect on the ringing programme in that more birds should be centred on the ringing areas.

Logistics

We would like to repeat the offer made last year regarding analysis and interpretation of data. We hope that taking responsibility for entering the data onto the CEMPA system will be helpful, and that the financial contribution to the scheme will help especially in the current difficult financial climate. We intend to consolidate this aspect if invited to continue with the project. 

Finally, we would like repeat our thanks to the management of the Parque Ambientale for allowing us access to the site during our stay, and to Vitor Encarnacao and Michael Armelin for providing us with the necessary permits and rings. We are immensely grateful also for the support during the planning stages and when on site from Nuno Grade, and  Ana Luisa Quaresma, who again made us very welcome and helped in a great many ways to make our visit successful.

Colin McShane ( on behalf of the ringing team); October 2011