Browsing by Author "Catry, Teresa"
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- Brood-guarding behaviour in Bulwer's Petrel (Bulweria bulwerii)at two East Atlantic coloniesPublication . Pinto, Maria Gomes Ribeiro Teixeira; Catry, Teresa; Pedro, Patrícia I.; Gatt, Marie Claire; Dias, Maria P.We characterized the brood-guarding behaviour of the Bulwer’s Petrel Bulweria bulwerii at two Atlantic colonies. Our results suggest that predation avoidance might be a major factor driving broodguarding duration on this species.
- Distribution and at-sea activity of a nocturnal seabird, the Bulwer's petrel Bulweria bulwerii, during the incubation periodPublication . Dias, Maria P.; Romero, Joana; Granadeiro, José Pedro; Catry, Teresa; Pollet, Ingrid L.; Catry, PauloBulwer'spetrelsarenocturnalseabirdsthatmostlypreyonmesopelagicfauna.Asaerialforagersand shallowdivers,theirfeedingopportunitiesarelimitedbynear-surfaceavailabilityoftheirprey,whichis highlyvariablebothtemporally(reflectingdiurnalandlunarcycles)andspatially.Herewestudiedhow Bulwer'spetrelscopewiththeseconstraintsbyanalysingtheirat-seadistributionandactivityduringthe incubationperiod.Wetrackedthemovementsof20birdsfromSelvagemGrande(NEAtlantic)duringa completelunarcycle,andrecorded30foragingtripsthatlasted11daysonaverage.Birdswereboth distributedaroundthecolonyandinwatersclosetotheAzoreanarchipelago(mid-Atlantic)located 1700kmaway,andweresignificantlymoreactiveatnight(especiallyjustaftersunsetandbeforesunrise), whenmesopelagicfaunaisalsoclosertotheseasurfaceduetotheirdielverticalmigrations.Bulwer's petrelsspentsignificantlymoretime flyingduringmoonlight,althoughtheeffectofthemoonwasrela- tivelyweak(ca.10–15%differencebetweenmoonlitanddarkperiodsofthenight),andnotobviouswhen birdswereforaginginmid-Atlanticwaters,whichwerealsotargetedmoreoftenduringfull-moon.These resultsrevealkeyadaptationsoftheBulwer'spetreltothehighlydynamicecologyofitsmesopelagicprey.
- Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-BissauPublication . Coelho, J. P.; Monteiro, R. J. R.; Catry, Teresa; Lourenço, Pedro Miguel; Catry, Paulo; Regalla, Aissa Said; Catry, Inês; Figueira, Paula; Pereira, Eduarda; Vale, Carlos; Granadeiro, José PedroThis work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14μgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.
- Evidence for contrasting accumulation pattern of cadmium in relation to other elements in Senilia senilis and Tagelus adansoni from the Bijagós archipelago, Guinea-BissauPublication . Catry, Teresa; Figueira, Paula; Carvalho, Lina; Monteiro, Rui J. R.; Coelho, Pedro Duarte; Lourenço, Pedro Miguel; Catry, Paulo; Tchantchalam, Quintino; Catry, Inês; Botelho, Maria J.; Pereira, Eduarda; Granadeiro, José Pedro; Vale, CarlosShellfish harvesting in intertidal areas is a widespread and economically important activity in many countries across West Africa. However, in some areas, there is virtually no information concerning the levels of contaminants (and other elements related to nutritional aspects) in the harvested species. We collected sediments and several individuals of the West African bloody cockle Senilia senilis and of the razor clam Tagelus adansoni during the dry season of 2015 nearby three islands in the Bijagós archipelago, Guinea-Bissau. Aluminium, Ca, Fe, Mg, As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined in sediments and whole soft tissues of the two bivalves. Sediments showed uniformly low trace element concentrations, pointing to an ecosystem with low levels of trace element contamination. T. adansoni presented higher concentrations of most elements than S. senilis, with the exception of Cd that showed up to 40 times higher values in S. senilis than in T. adansoni from the same sites. Furthermore, Cd concentrations (25±8.7 mg kg(-1), dw) in S. senilis are clearly above the maximum level established for human consumption. Future studies should clarify whether biological factors are the major responsible for this unusual situation.
- Individual variation in migratory movements and winter behaviour of Iberian Lesser Kestrels Falco naumanni revealed by geolocatorsPublication . Catry, Inês; Dias, Maria P.; Catry, Teresa; Afanasyev, Vsevolod; Fox, James; Franco, Aldina M. A.; Shutherland, William J.The population decline of the Lesser Kestrel Falco naumanni has been the subject of studies across its Western Palaearctic breeding range, but little is known about its use of pre-migratory areas or African wintering quarters. We used geolocators to describe the temporal and spatial patterns of Portuguese Lesser Kestrel migration and wintering behaviour. Data on the complete migration were obtained from four individuals and another three provided further information. Prior to southward migration, Lesser Kestrels showed two different behaviours: northward-orientated movements to Spain and movements in the proximity of the breeding area. Autumn migration took place mostly in late September; spring departures occurred mainly in the first half of February. Wintering grounds included Senegal, Mauritania and Mali, with individuals overlapping considerably in Senegal. Movements registered within the wintering grounds suggest itinerant behaviour in relation to local flushes of prey. During spring migration, birds crossed the Sahara Desert through Mauritania, Western Sahara and Morocco before passing over the Mediterranean to reach Portugal. Autumn migration lasted 4.8 ± 1.1 days, and spring migration lasted 4.1 ± 0.3 days. The mean daily flight range varied between approximately 300 and 850 km for an entire journey of around 2500 km. Effective protection of roosting sites in both pre-migratory and wintering areas and maintaining grasshopper populations in Sahelian wintering quarters appear crucial in preserving this threatened migratory raptor across its African–Eurasian flyway. There was no evidence of any deleterious effects of fitting birds with loggers.
- Long-term declines of wader populations at the Tagus estuary, Portugal: A response to global or local factors?Publication . Catry, Teresa; Alves, José A.; Andrade, Joana; Costa, Helder; Dias, Maria P.; Fernandes, Pedro; Leal, Ana; Lourenço, Pedro Miguel; Martins, Ricardo C.; Moniz, Filipe; Pardal, Sara; Rocha, Afonso; Santos, Carlos D.; Encarnação, Vitor; Granadeiro, José PedroMigratory wader populations face global threats, mainly related to increasing rates of habitat loss and disturbance driven by human activities. To a large extent, the long-term survival of these populations requires the conservation of networks of sites along their migratory flyways. The Tagus estuary, Portugal, is among the most important wetlands for waders in the East Atlantic Flyway. Annual winter wader counts have been carried in this wetland since 1975 and a monthly roost-monitoring programme was implemented in 2007. Wintering populations of three out of the five most abundant species, Dunlin Calidris alpina, Grey Plover Pluvialis squatarola and Redshank Tringa totanus, showed significant population declines over the past three decades, which are most likely due to the loss and degradation of roost sites as a result of increasing human activity. The situation is unlikely to improve, as a high proportion of the wintering waders use roost sites that are situated in highly urbanised areas with no legal protection. The use of different roost sites by waders is highly variable both temporally and spatially, thus emphasizing the need for a network of good quality roost sites. Additionally, during migration, 60–80% of all the waders of the Tagus estuary concentrate at a single refuge, thus increasing the risk for wader populations during these periods. ------ RESUMO ------ As populações de aves limícolas migradoras enfrentam ameaças globais, maioritariamente relacionadas com a crescente perda de habitat e perturbação humana. Para garantir a sobrevivência a longo-termo destas populações é imprescindível a conservação de uma rede de áreas húmidas ao longo das suas rotas migratórias. O estuário do Tejo, em Portugal, é uma das mais importantes áreas húmidas para aves limícolas na rota Migratória do Atlântico Este. Desde 1975, foram efectuadas contagens anuais de aves limícolas no inverno nesta zona húmida e, em 2007, foi implementado um programa de monitorização mensal dos refúgios de preia-mar. As populações invernantes de três das cinco espécies de limícolas mais abundantes no estuário, o Pilrito-de-peito-preto Calidris alpina, a Tarambola-cinzenta Pluvialis squatarola e o Perna-vermelha Tringa totanus, mostraram tendências significativas de decréscimo nas últimas três décadas, potencialmente devido à degradação e perda de refúgios como resultado da crescente actividade antropogénica. Esta situação poderá deteriorar-se, uma vez que uma grande proporção das aves limícolas invernantes utiliza refúgios em áreas densamente urbanizadas sem qualquer estatuto legal de protecção. A utilização dos diferentes refúgios do estuário do Tejo por aves limícolas tem uma grande variação espacial e temporal, o que reforça a importância da existência de uma rede de refúgios de elevada qualidade nesta área húmida. Durante a migração, 60 a 80% das aves limícolas concentram-se num único refúgio, ficando assim particularmente vulneráveis neste período.
- Major, minor, trace and rare earth elements in sediments of the Bijagós archipelago, Guinea-BissauPublication . Carvalho, Lina; Figueira, Paula; Monteiro, Rui J. R.; Reis, Ana Teresa; Almeida, Joana C.; Catry, Teresa; Lourenço, Pedro Miguel; Catry, Paulo; Barbosa, Castro; Castro, Inês; Pereira, Eduarda; Pereira, Eduarda; Granadeiro, José Pedro; Vale, CarlosSixty sediment samples from four sites in the Bijagós archipelago were characterized for fine fraction, loss on ignition, major, minor and trace elemental composition (Al, Fe, Ca, Mg, Ti, P, Zr, Mn, Cr, Sr, Ba, B, V, Li, Zn, Ni, Pb, As, Co, U, Cu, Cs and Cd), and the elements of the La–Lu series. Element concentrations were largely explained by the Al content and the proportion of fine fraction content, with the exception of Ca and Sr. Sediments showed enhanced Ti, U, Cr, As and Cd concentrations with respect to estimated upper crust values, most likely mirroring a regional signature. Rare earth elements were in deficit relatively to the North American Shale Composite (NASC), mainly in coarser material. No pronounced Ce-anomaly was observed, while Eu-anomalies were positive in most analyzed sediments.
- Within an between-year winter-site fidelity of Chiffchaffs Phylloscopus collybitaPublication . Catry, Paulo; Catry, Inês; Catry, Teresa; Martins, TeresaCurrent knowledge concerning between-year winter site fidelity in passerines suggests there might be important inter-specific and regional variations in recurrence rates (the proportion of birds recaptured in years subsequent to marking). However, there are virtually no studies reporting low recurrence rates that show this not to be simply the result of low recapture probabilities. This problem can be particularly acute for partly nomadic and mostly non-territorial species in their winter quarters. The present study shows that, in spite of the apparently nomadic behaviour of wintering Chiffchaffs Phylloscopus collybita, some individuals can become temporarily sedentary. Temporarily sedentary Chiffchaffs have very small linear home-ranges (ca. 200m) and their calculated recapture probability (by re-sighting of colour-ringed birds) is high. In spite of that, recurrence rate of temporarily sedentary birds is very low, suggesting that the majority of the surviving individuals are not site faithful. This is in contrast to what has been found in several detailed studies in other Sylviidae and also Parulidae involving mostly territorial birds. The type of approach developed here should be used in other studies before any comparisons and generalisations involving winter-site fidelity results are attempted.