Bird community of the Douro Estuary Local Nature Reserve (Vila Nova de Gaia) and mouth of Granja stream (urban stream, Porto) (2016-2017)

Data Records

The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 213 records.

1 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.

This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.

Versions

The table below shows only published versions of the resource that are publicly accessible.

How to cite

Researchers should cite this work as follows:

Freitas B, Múrias T, Rodrigues T, Faria P, Gonçalves D (2023): Bird community of the Douro Estuary Local Nature Reserve (Vila Nova de Gaia) and mouth of Granja stream (urban stream, Porto) (2016-2017). v1.1. CIBIO (Research Center in Biodiversity and Genetic Resources) Portugal. Dataset/Samplingevent. http://ipt.gbif.pt/ipt/resource?r=rnled_aves_2016-17&v=1.1

Rights

Researchers should respect the following rights statement:

The publisher and rights holder of this work is CIBIO (Research Center in Biodiversity and Genetic Resources) Portugal. This work is licensed under a Creative Commons Attribution (CC-BY 4.0) License.

GBIF Registration

This resource has been registered with GBIF, and assigned the following GBIF UUID: 83ff3467-1941-4c9a-a47a-ec96c97e0237.  CIBIO (Research Center in Biodiversity and Genetic Resources) Portugal publishes this resource, and is itself registered in GBIF as a data publisher endorsed by GBIF Portugal.

Keywords

Aquatic birds; Aves; Point counts; Porto/Vila Nova de Gaia; Granja stream mouth; Local Nature Reserve of the Douro Estuary (RNLED)

Contacts

Geographic Coverage

The study area covers the terminal part of the Douro Estuary, encompassing the Douro Estuary Local Nature Reserve (RNLED, Reserva Natural Local do Estuário do Douro), located some 500 m from the mouth of the estuary (Vila Nova de Gaia municipality) and the mouth of an urban stream (Granja stream) located in the northern part of the estuary, 2 km upstream (Porto municipality).

Taxonomic Coverage

The taxonomic coverage of this dataset spans 1 phylum, 1 class, 4 orders, 8 families, 21 genera and 26 species.

Temporal Coverage

Project Data

This dataset includes systematic counts of aquatic birds carried out in the Douro Estuary Local Nature Reserve (RNLED, Reserva Natural Local do Estuário do Douro, Vila Nova de Gaia), a protected area in the mouth of Douro estuary, Northern Portugal, and in the mouth of the Granja stream (Porto), an urban stream that meets the Douro, in the northern side of the estuary, 2 km upstream of its’ mouth. Data was collected during the winter of 2016/2017 and the early part of 2017 spring migratory season. A total of 33447 records of individual birds were obtained, encompassing 26 species and 21 genera.

The personnel involved in the project:

Sampling Methods

Nine counting points were established in the study area (7 in RNLED and 2 in Granja stream), using Google maps and ArcGIS 9.3 (Environmental Systems Research Institute, Redlands, CA, EUA). The points had to fulfill two criteria: (1) to maximize the area covered and, (2) to cover the different substrate types used by the birds. Thus, they were established in a way that each covered at least one of the pre-defined substrates (but usually more). Between them, they enabled the detection of all aquatic birds present during counts in their field of vision (complete counts method). In total, 31 counts were performed in 2016-2017 (20 in RNLED and 11 in Granja stream). From December 2016 to February 2017 (wintering period), 12 counts were conducted in RNLED (6 at low-tide and 6 at high-tide) and 7 in Granja stream (4 at low-tide and 3 at high-tide). In March and April 2017 (migration period), 8 counts were performed in RNLED (4 at low-tide and 4 at high-tide), and 4 in Granja stream (2 at low-tide and 2 at high-tide). Counts were performed around the tidal peak (± 2 hours) in days with good weather conditions (i.e., without heavy rain, strong wind and fog). To cover the daily heterogeneity of the birds' behaviour, the counts were performed between 06:57h and 17:21h, except in the Granja stream where all counts were made between 12:50h and 16:16h. The counts were carried out with binoculars (Opticron 10×50) and a telescope (Swarovsky 20×60). All the individuals present on each substrate were quantified by direct counting or estimated (in the case of large flocks) (Bibby et al. 1992). Additionally, the behaviour of the focal birds, (feeding or resting and/or preening), the substrate type(s) used (assessed in the field, using natural markings), as well as any disturbance events (e.g., people, domestic animals), were recorded. The birds were identified to the species level, the exception being the juveniles of the large gulls (Larus michahellis and L. fuscus), which were grouped under the name of “Larus sp. (juv)”. Tidal levels and general weather conditions were taken from online data (http://www.tabuademares.com/pt/porto/porto-rio-douro and https://www.ipma.pt/en/otempo/ prev.localidade.hora/, respectively). The substrate types were defined visually, based on two field visits carried out at each local, one at high tide and the other at low tide, to estimate the respective areas. The types considered were: (a) sand with grass shrubs (sand with portions of grass and/or shrubs; RNLED, only), (b) sand, (c) muddy sand (mixture of sand and silt, with the predominance of the former), (d) mud (RNLED, only), (e) sand with rocks (mostly sand with some natural rocks; Granja stream, only), (f) rocks with sand (mostly rocks with some sand; Granja stream, only), (g) rock (natural rocks or human-made rock walls), (h) salt Marsh (mud soil flooded and drained by tides; RNLED only), (i) dry dock (old construction to repair artisanal boats; Granja stream, only) and (j) water (open water, river or sea).

Method step description:

1. To be completed

Bibliographic Citations

1. Bibby, C. J., Burgess, N. D. and Hill, D. A. (1992). “Bird Census Techniques.” Academic Press, London.

Additional Metadata