Biodiversity Data Journal : Data Paper (Biosciences)
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Data Paper (Biosciences)
Surveying Cory Shearwater colonies with camera traps and identifying potential invasive nest predators
expand article infoLucas Lamelas-Lopez‡, Paulo A. V. Borges‡,§
‡ Centre for Ecology, Evolution and Environmental Changes (cE3c)/Azorean Biodiversity Group, CHANGE – Global Change and Sustainability Institute, Faculty of Agricultural Sciences and Environment, University of the Azores, Rua Capitão João d´Ávila, Pico da Urze, 9700-042, Angra do Heroísmo, Azores, Portugal
§ IUCN SSC Mid-Atlantic Islands Invertebrates Specialist Group, Angra do Heroísmo, Azores, Portugal
Corresponding author: Lucas Lamelas-Lopez (lucaslamelaslopez@gmail.com)
Academic editor: João Pedro Barreiros
Received: 09 Mar 2023 | Accepted: 17 Mar 2023 | Published: 03 Apr 2023
© 2023 Lucas Lamelas-Lopez, Paulo Borges
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Lamelas-Lopez L, Borges PAV (2023) Surveying Cory Shearwater colonies with camera traps and identifying potential invasive nest predators. Biodiversity Data Journal 11: e103270. https://doi.org/10.3897/BDJ.11.e103270
 Open Access

Abstract

Background

The Azores holds the largest population of Cory's shearwater Calonectris borealis (Cory, 1881) (Aves, Procellariiformes, Procellariidae) in the world. One of the major threats of this species in the Azores is the predation by invasive mammals, which were introduced during European colonisation of the islands.

The present study provides a dataset from a camera-trapping survey performed in colonies of Cory’s shearwater. The sampling was conducted between 7 April and 23 October 2019, covering the entire breeding season, in three colonies of the Terceira Island (Azores). A total of 32 nests were sampled using motion-triggered cameras. The aims of this study are to provide information about the ecological patterns of the Cory shearwater and to identify potential nest predators.

New information

Our results include a total of 6972 records of 15 species (nine species of birds, five of mammals and one reptile), of which 5414 records are of Cory’s shearwater, 478 of potential mammal predators and 1080 of another vertebrate species. Information about the biology of the species is also provided, as species circadian behaviour and habitat description.

Keywords

biodiversity, biological invasions, camera-traps, invasive predators, inventory, Oceanic Islands, seabirds.

Introduction

Biological invasions, climate change and habitat fragmentation, degradation and destruction are the main drivers of biodiversity loss worldwide (e.g. Vitousek et al. (1997), Bellard et al. (2014), Doherty et al. (2016)). These three biodiversity erosion drivers can act synergistically, but invasive species alone can affect dramatically the native species communities and ecosystems functioning (e.g. Capizzi (2020)). In comparison with mainland areas, island ecosystems are especially vulnerable to biological invasions (Blumstein and Daniel 2005, Bellard et al. 2014, Spatz et al. 2017). Mammal predators constitute an important threat to island native vertebrates, being responsible by the decline or extinction of hundreds of island species worldwide (Medina et al. 2014, Dawson et al. 2014, Doherty et al. 2016). Island terrestrial and marine birds have been particularly affected by the introduction of invasive mammals (Medina et al. 2014, Spatz et al. 2017).

The Azores Archipelago comprises nine main islands of volcanic origin and it is located in the North Atlantic Ocean. The islands are considered a high priority area for seabird conservation, harbouring important populations of many seabird species, as for example, the globally endangered Monteiro's storm-petrel Hydrobates monteiroi Bolton et al. 2008 (Bolton et al. 2008, BirdLife-International 2016) or the Cory’s shearwater Calonectris borealis (Cory, 1881), for which the Azores population is one of the largest worldwide.

Studies about seabirds and terrestrial birds’ populations in the Archipelago showed that mammal predators are probably the main cause of breeding failure (Monteiro et al. 1996, Amaral et al. 2010, Hervías et al. 2013a, Hervías et al. 2013b, Lamelas-López et al. 2020, Lamelas-López et al. 2021) or extinction (Monteiro et al. 1996). Mammals were introduced in the Archipelago as a consequence of the Portuguese arrival and settlement in the 15th century. Currently, the mammal predators present in the Archipelago include rodents (house mouse Mus musculus Linnaeus, 1758, black rat Rattus rattus Linnaeus, 1758 and Norway rat Rattus norvegicus Berkenhout, 1769) and carnivores (ferret Mustela furo Linnaeus, 1758, weasel Mustela nivalis Linnaeus, 1766, feral cat Felis silvestris catus Schreber, 1775 and feral dog Canis lupus familiaris Linnaeus, 1758).

Identification of predators and the knowledge about their ecological patterns are crucial to the conservation of native terrestrial and marine birds of the Azores (Rader et al. 2007, Richardson et al. 2009). In this context, camera-trapping has been demonstrated to be an efficient tool to answer a variety of research questions in the fields of animal ecology, behavioural studies and conservation biology or for the inventory and monitoring of wildlife (Tobler et al. 2008, O'Connell et al. 2011, Rendall et al. 2014), particularly applied to identify invasive predators and to assess their impacts on native biodiversity (Oppel et al. 2014, Lamelas-López et al. 2020, Lamelas-López et al. 2021).

General description

Purpose: 

The main objectives of this study are to provide a dataset of species present in three Cory Shearwater colonies of Terceira Island, obtained from camera-trap records; and to obtain information about the biology of the Cory Shearwater, through the description of habitat and circadian behaviour and to identify potential introduced mammal predators.

Project description

Title: 

Surveying seabird colonies with camera traps: The impacts of invasive predators on Cory Shearwater

Personnel: 

Lucas Lamelas-López, Paulo A.V. Borges

Study area description: 

The study was conducted in three of Cory’s shearwater colonies, on Terceira Island (total area: 400.2 km²; maximum elevation: 1021 m a.s.l; -38°40'N, 27°10'W), which belongs to the Azores Archipelago (North Atlantic). Chanoca colony is located on the southern coast of the Island (maximum elevation: 21 m a.s.l; 38°39'36.0288"N, 27°17'42.1872"W) and it is formed by cliffs and rocky bays, slightly covered by some herbaceous plants, such as sour fig Carpobrotus edulis (L.) N.E. Br. Raminho colony (maximum elevation: 90 m a.s.l; 38°46'50.5668"N, 27°21'23.6736"W) is located in the north-west and it is characterised by cliffs dominated by native forests, mainly composed by Erica azorica Hochst. ex Seub, and Morella faya (Aiton) Wilbur. Finally, the Agualva colony (maximum elevation: 34 m a.s.l; 38°47'40.6068"N, 27°11'28.3452"W) is located in the north of the Island and it consists of a rocky area scarcely covered by patches of native vegetation (E. azorica).

Design description: 

Motion-triggered infrared cameras (Bushnell Trophy HD, Moultrie 880i and 990i) were installed in the colonies at the beginning of the breeding season (e.g. Lamelas-López et al. (2020)). We installed one camera per nest, which remained recording continuously until the end of the breeding season or until the nest was abandoned or depredated and then the camera was moved to another nest. The cameras were deployed at 50-100 cm of the nest entrances. Cameras were configured to take 8 MB-photos, with 30 seconds of delay between them (Lamelas-López et al. 2021). Date and time were automatically recorded for each event. The nests were monitored each 10 days, in order to assess the nest condition and to replace the SD cards and the batteries of the cameras, if necessary. The study was conducted from 7 April and 23 October 2019. The obtained photos were posteriorly analysed and identified by L.L.L.

Funding: 

Fieldwork: Fundação para a Ciência e Tecnologia - FCT (SFRH/BD/115022/2016)

Database management: FCT-UIDB/00329/2020-2024 (Thematic Line 1 – integrated ecological assessment of environmental change on biodiversity) and also FCT-UIDP/00329/2020-2023.

Sampling methods

Description: 

The study was conducted in three of Cory’s shearwater colonies, on Terceira Island (total area: 400.2 km²; maximum elevation: 1021 m a.s.l; -38°40'N, 27°10'W). Chanoca colony is located on the southern coast of the Island (maximum elevation: 21 m a.s.l; 38°39'36.0288"N, 27°17'42.1872"W) and it is formed by cliffs and rocky bays, slightly covered by some herbaceous plants such as sour fig Carpobrotus edulis (L.) N.E. Br. Raminho colony (maximum elevation: 90 m a.s.l; 38°46'50.5668"N, 27°21'23.6736"W) is located in the north-west and it is characterised by cliffs dominated by native forests, mainly composed by Erica azorica Hochst. ex Seub and Morella faya (Aiton) Wilbur. Finally, the Agualva colony (maximum elevation: 34 m a.s.l; 38°47'40.6068"N, 27°11'28.3452"W) is located in the north of the Island and it consists of a rocky area scarcely covered by patches of native vegetation (E. azorica).

Sampling description: 

Motion-triggered infrared cameras (Bushnell Trophy HD, Moultrie 880i and 990i) were installed in the colonies at the beginning of the breeding season (e.g. Lamelas-López et al. (2020)). We installed one camera per nest, which remained recording continuously until the end of the breeding season or until the nest was abandoned or depredated and then the camera was moved to another nest. The cameras were deployed at 50-100 cm of the nest entrances. Cameras were configured to take 8 MB-photos, with 30 seconds of delay between them (Lamelas-López and Salgado 2020, Lamelas-López et al. 2021). Date and time were automatically recorded for each event. The nests were monitored each 10 days, in order to assess the nest condition and to replace the SD cards and the batteries of the cameras, if necessary. The study was conducted from 7 April and 23 October 2019. The obtained photos were posteriorly analysed and identified by L.L.L.

Quality control: 

All the photos were carefully verified by the authors.

Step description: 

Between 7 April and 23 October 2019, a total of 32 camera-traps were installed in three of Cory’s shearwater colonies on Terceira Island, covering the entire breeding period. We searched occupied nests and installed one camera per nest, which remained recording continuously until the end of the breeding season or until the nest was abandoned or depredated and then the camera was moved to another nest. Cameras were deployed at 50-100 cm of the nest entrance and were programmed to take photos, which recorded date and time of the event. Nests were monitored each 10 days, in order to assess the nest condition and to replace the SD cards and batteries of the cameras. The obtained photos were posteriorly analysed and identified by L.L.L.

The data have been published as a Darwin Core Archive (DwC-A), which is a standardised format for sharing biodiversity data as a set of one or more data tables. We provided an event data table, which contains 2976 records; and an occurrence data table, with 6972 records.

Geographic coverage

Description: 

Terceira Island, Azores, Portugal.

Coordinates: 

3843'17"N Latitude; 27°13'14"W Longitude and .

Taxonomic coverage

Description: 

The following Classes and Orders are covered: Aves: Procellariiformes, Columbiformes, Passeriformes; Mammalia: Carnivora, Lagomorpha, Rodentia; Reptilia: Squamata.

Taxa included:
Rank Scientific Name Common Name
class Aves Birds
class Mammalia Mammals
class Reptilia Reptiles
order Procellariiformes Petrels
order Columbiformes Doves
order Passeriformes Passerines
order Carnivora Carnivores
order Lagomorpha Rabbits
order Rodentia Rodents

Temporal coverage

Data range: 
2019-4-07 - 2019-10-23.

Usage licence

Usage licence: 
Creative Commons Public Domain Waiver (CC-Zero)

Data resources

Data package title: 
Camera-traps_Seabirds_2019
Resource link: 
http://ipt.gbif.pt/ipt/resource?r=camera-trap_seabirds_2023
Alternative identifiers: 
https://www.gbif.org/dataset/7fa446fd-caf6-43a4-83f6-b2cbb06c51c7
Number of data sets: 
2
Data set name: 
Event Table
Character set: 
UTF-8
Download URL: 
http://ipt.gbif.pt/ipt/resource?r=camera-trap_seabirds_2023
Data format: 
Darwin Core Archive
Data format version: 
version 1.2
Description: 

The dataset is available on the Global Biodiversity Information Facility platform, GBIF (Lamelas-López and Borges 2023). The following data table includes records at species level. The dataset submitted to GBIF is structured as a sample event dataset, with two tables: event and occurrence tables. The data in this sampling event resource have been published as a Darwin Core Archive (DwCA), which is a standardised format for sharing biodiversity data as a set of one or more data tables. The event table contains 2976 records. This IPT (Integrated Publishing Toolkit) archives the data and, thus, serves as the data repository. The data and resource metadata are available for download from Lamelas-López and Borges (2023).

Column label Column description
id Unique identification code for sampling event data.
eventID Identifier of the events, unique for the dataset.
samplingProtocol The sampling method used to obtain the records.
sampleSizeValue The number of days that the cameras remain active in each sampling.
sampleSizeUnit The unit of the sample size value.
eventDate Date or date range the record was collected.
year Year of the event.
month Month of the event.
day Day of the event.
habitat The habitat type in which the event occurred.
fieldNotes Notes about the use or non-use of bait in the sampling sites.
locationID Identifier of the location.
islandGroup Name of archipelago.
island Name of the island.
country Country of the sampling site.
countryCode ISO code of the country of the sampling site.
stateProvince Name of the region of the sampling site.
municipality Municipality of the sampling site.
locality Name of the locality.
decimalLatitude The geographic latitude, in decimal degrees.
decimalLongitude The geographic longitude, in decimal degrees.
geodeticDatum The ellipsoid, geodetic datum or spatial reference system (SRS) upon which the geographic coordinates given in decimalLatitude and decimalLongitude are based.
coordinateUncertaintyInMeters Uncertainty of the coordinates, in metres.
coordinatePrecision Precision of the coordinates.
georeferenceSources A list (concatenated and separated) of maps, gazetteers or other resources used to georeference the Location, described specifically enough to allow anyone in the future to use the same resources.
Data set name: 
Occurrence Table
Character set: 
UTF-8
Download URL: 
http://ipt.gbif.pt/ipt/resource?r=camera-trap_seabirds_2023
Data format: 
Darwin Core Archive
Data format version: 
version 1.2
Description: 

The dataset is available on the Global Biodiversity Information Facility platform, GBIF (Lamelas-López and Borges 2023). The following data table includes records at species level. The dataset submitted to GBIF is structured as a sample event dataset, with two tables: event and occurrence tables. The data in this sampling event resource have been published as a Darwin Core Archive (DwCA), which is a standardised format for sharing biodiversity data as a set of one or more data tables. The occurrence table contains 6972 records. This IPT (Integrated Publishing Toolkit) archives the data and, thus, serves as the data repository. The data and resource metadata are available for download from Lamelas-López and Borges (2023).

Column label Column description
id Unique identification code for species abundance data.
institutionID The identity of the institution publishing the data.
institutionCode The code of the institution publishing the data.
datasetName Name of the dataset.
basisOfRecord The nature of the data record.
occurrenceID Identifier of the record, coded as a global unique identifier.
organismQuantity A number or enumeration value for the quantity of organisms.
organismQuantityType The type of quantification system used for the quantity of organisms.
behaviour Information about the circadian activity of the individuals.
establishmentMeans The process of establishment of the species in the location, using a controlled vocabulary: 'native', 'introduced', 'endemic', 'Macaronesian native'.
occurrenceStatus Information about the presence/absence of a taxon at a camera location.
eventID Identifier of the events, unique for the dataset.
identifiedBy Name of the researcher who performed the identification of the photos.
dateIdentified Year of the identification of the photos content.
identificationRemarks Additional information about species identity, according to species code on the Azorean Biodiversity Portal (https://azoresbioportal.uac.pt/).
scientificName Complete scientific name including author and year.
kingdom Kingdom name.
phylum Phylum name.
class Class name.
order Order name.
family Family name.
genus Genus name.
specificEpithet Specific epithet.
infraspecificEpithet Infraspecific epithet.
taxonRank Lowest taxonomic rank of the record.
scientificNameAuthorship Name of the author of the lowest taxon rank included in the record.

Additional information

A total of 6972 records of vertebrates were obtained, belonging to three classes, seven orders, 11 families and 15 species (Table 1). Nine species of birds were recorded, of which four are considered Azorean endemic subspecies (Columba palumbus azorica Hartert, 1905; Fringilla coelebs moreletti Pucheran, 1859; Sylvia atricapilla gularis Alexander, 1898; and Turdus merula azorensis Hartert, 1905), two native non-endemic (Calonectris borealis (Cory, 1881); and Erithacus rubecula rubecula (Linnaeus, 1758), one Macaronesian endemic (Serinus canaria (Linnaeus, 1758)) and two introduced (Columba livia domestica Gmelin, 1758; and Passer domesticus domesticus Linnaeus, 1758) (Borges et al. 2010). Five species of mammals were detected, namely Felis catus Linnaeus, 1758; Mus musculus Linnaeus, 1758; Mustela nivalis Linnaeus, 1766; Oryctolagus cuniculus (Linnaeus, 1758); and Rattus rattus (Linnaeus, 1758), which are all introduced species in the Azores. Finally, we recorded one single species of reptile, Teira dugesii (Milne-Edwards, 1829), which is also introduced coming from Madeira (native range).

Table 1.
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Abundance, colonisation status (CS) and IUCN categories (IUCN) of species recorded in the three Cory’s shearwater colonies of Terceira Island (Azores), in 2019, based on camera-trapping data. Abbreviations: endemic subspecies of Azores (end); endemic of Macaronesia (mac); introduced (int); native non-endemic (nat); LC Least Concern; AGU Agualva Colony, CHA Chanoca colony, RAM Raminho colony.

Class

Order

Species

CS

IUCN

AGU

CHA

RAM

Aves

Columbiformes

Columba livia domestica Gmelin, 1758

int

 LC

0

13

0

Aves

Columbiformes

Columba palumbus azorica Hartert, 1905

end

 LC

2

2

13

Aves

Passeriformes

Fringilla coelebs moreletti Pucheran, 1859

end

 LC

1

3

7

Aves

Passeriformes

Serinus canaria (Linnaeus, 1758)

mac

 LC

1

0

1

Aves

Passeriformes

Passer domesticus domesticus Linnaeus, 1758

int

 LC

1

16

4

Aves

Passeriformes

Sylvia atricapilla gularis Alexander, 1898

end

 LC

33

0

8

Aves

Passeriformes

Erithacus rubecula rubecula (Linnaeus, 1758)

nat

 LC

34

0

211

Aves

Passeriformes

Turdus merula azorensis Hartert, 1905

end

 LC

103

7

322

Aves

Procellariiformes

Calonectris borealis (Cory, 1881)

nat

 LC

939

1801

2674

Mammalia

Carnivora

Felis catus Linnaeus, 1758

int

 LC

29

27

12

Mammalia

Carnivora

Mustela nivalis Linnaeus, 1766

int

 LC

4

0

0

Mammalia

Lagomorpha

Oryctolagus cuniculus (Linnaeus, 1758)

int

 LC

2

0

0

Mammalia

Rodentia

Mus musculus Linnaeus, 1758

int

 LC

4

82

24

Mammalia

Rodentia

Rattus rattus (Linnaeus, 1758)

int

 LC

45

29

220

Reptilia

Squamata

Teira dugesii (Milne-Edwards, 1829)

int

 LC

15

283

0

Most of records (n = 5414) were of C. borealis, given that the cameras were deployed focusing on nest entrances. The most abundant bird species detected were E. r. rubecula (n = 245) and T. merula azorensis (n = 432), which are native and endemic species, respectively. Introduced bird species showed low abundance (C. livia domestica n = 13 records; P. d. domesticus n = 21 records). This is probably associated with the habitat types, given that native bird species are more frequent in native vegetation areas, as are the studied areas, while introduced bird species are commonly associated with more human-disturbed habitats.

Most abundant mammal species were rodents R. rattus (n = 294) and M. musculus (n = 110) and the domestic cat (n = 68). These species were detected in all C. borealis colonies and they are known predators of terrestrial birds and seabirds in many islands worldwide (Bolton et al. 2008, Medina et al. 2014; Spatz et al. 2017) and particularly in the Azores islands (Monteiro et al. 1996, Hervías et al. 2013a, Hervías et al. 2013b, Lamelas-López et al. 2020, Lamelas-López et al. 2021; Fig. 1). M. nivalis has also been reported has a potential predator of native birds in the Archipelago, but our data suggest that the impact will be probably low (we only recorded four events in one colony).

Figure 1.  

Record of Felis catus predating on a chick of Calonectris borealis in Chanoca colony.

Teira dugesii was detected in the colonies (n = 298), mainly in the Chanoca colony, which is dominated by rocky areas.

Additionally, in the dataset, we also provided information about the behaviour of the species, particularly of the circadian activity of the species. Calonectris borealis demonstrated to be more active during the dawn and dusk (n = 1738 records) and night (n = 3235 records), in comparison with day (n = 441 records). In general, introduced mammal predators were also more frequently observed during these periods. For example, R. rattus was mainly detected during the night (n = 217) or crepuscule (n = 64) in comparison with the day (n = 13). However, the F. catus was detected during all of the day (crepuscule n = 26, night n = 21, day n = 21).

Identification of introduced predator species and information of their abundance, habitat preferences or behaviour are crucial for information to design effective management plans and conservation actions (Thompson 2007, Lamelas-López et al. 2020).

Acknowledgements

We thank the Natural Park of Terceira Island for logistic support; and to Ana Sánchez, Giulia Spadoni, Jose Ortolá, Natalia Fierro and Clara Polaino for field assistance. LLL was supported by a grant from the Fundação para a Ciência e Tecnologia - FCT (SFRH/BD/115022/2016) and is currently funded by the project FCT-UIDP/00329/2020-2023. PAVB is supported by the project FCT-UIDB/00329/2020-2024 (Thematic Line 1 – integrated ecological assessment of environmental change on biodiversity).

Author contributions

LLL conceived the sampling protocols, performed the fieldwork and led the manuscript writing. LLL and PAVB contributed to dataset preparation and data analysis. PAVB contributed to final manuscript.

References

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