DOI: 10.5061/dryad.t4b8gtj8x
title: Data for: Geolocation and immersion loggers reveal year-round residency and consequent nutrient deposition rates of adult red-footed boobies in the Chagos Archipelago, tropical Indian Ocean

description: Bio-logging has revealed much about high-latitude seabird migratory
 strategies, but migratory behaviour in tropical species may differ, with
 implications for understanding nutrient deposition. Here we use combined
 light-level and saltwater immersion loggers to study the year-round
 movement behaviour of adult red-footed boobies (Sula sula rubripes) from
 the Chagos Archipelago, tropical Indian Ocean to assess migratory
 movements and estimate nutrient deposition rates based on the number of
 days they spent ashore. Light levels suggest that red-footed boobies are
 resident in the Chagos Archipelago year-round, although there are large
 latitudinal errors this close to the equator. Immersion data also indicate
 residency with tracked birds returning to land every one or two days.
 Spending an average of 79.86 ± 2.80 days and 280.84 ± 2.64 nights per year
 on land allows us to estimate that the 21,670 pairs of red-footed boobies
 deposit 37.34 ± 0.56 tonnes year-1 of guano-derived nitrogen throughout
 the archipelago. Our findings have implications for tropical seabird
 conservation and phylogenetics, as well as for assessing the impact of
 seabird nutrients on coral reef ecosystems.
description: RFBs were tracked from Barton Point, Diego Garcia, Chagos
 Archipelago between January 2018 and February 2020. Adults were fitted
 with combined geolocation and immersion loggers (Intigeo C330, Migrate
 technology, Cambridge, UK; 3.3g) attached to a multi-layered impact
 acrylic leg ring (Interrex-rings, Poland). Immersion data were processed
 using the ExMove toolkit (Langley et al. In press, Journal Animal Ecology)
 to create a standardised data frame.
description: # Data for: Geolocation and immersion loggers reveal year-round residency
 and consequent nutrient deposition rates of adult red-footed boobies in
 the Chagos Archipelago, tropical Indian Ocean
 [https://doi.org/10.5061/dryad.t4b8gtj8x](https://doi.org/10.5061/dryad.t4b8gtj8x) Data of red-footed booby, *Sula sula,* immersion from year-round GLS logger deployments. Immersion data represent times when loggers were wet or dry, which we use to estimate year-round colony attendance. ## Description of the data and file structure Data have been processed using the ExMove workflow ([https://exmove.github.io](https://exmove.github.io) ) to create a standardised and clean file with the following columns: * ID: individual bird ID * Date * Time (GMT) * Immersion: logger immersion values per 10 minute period, where 0 = dry and 20 = wet. * DateTime (GMT) * Species: where "RFB" denotes red-footed booby * Population: where "DG" denotes Diego Garcia * Age * Sex: Female / Male / Unknown * Deploy_BrStage: Breeding stage at logger deployment: S0 = pre-egg, S1 = incubation, S2 = chick-rearing * Retrieve_BrStage: Breeding stage at logger retrieval: S0 = pre-egg, S1 = incubation, S2 = chick-rearing, NB = non-breeding * Deploydatetime: date and time of logger deployment (GMT) * Retrievedatetime: date and time of logger retrieval (GMT) ## Sharing/Access information Accompanying location data from GLS devices are available via the seabird tracking database ([www.seabirdtracking.org](http://www.seabirdtracking.org), Dataset ID = 2026) ## Code/Software All code accompanying this dataset and the manuscript are available at: [https://github.com/AliceTrevail/RFB-long-term-GLS.git](https://github.com/AliceTrevail/RFB-long-term-GLS.git)