DOI: 10.5061/dryad.h70rxwdwf
title: A lack of suitable roosts increases the threat of intertidal foraging habitat loss to migratory shorebirds

description: The loss of intertidal foraging habitats at stopover sites is the primary
 cause of population declines in many migratory shorebirds. However, the
 absence of high-tide roosts can exacerbate this impact by increasing the
 energy consumed for alarm flights and longer commutes between foraging and
 roosting sites, which has been poorly quantified during time-constrained
 spring stopovers. We monitored alarm flights at roosts using camera traps
 and tracked the commutes between roosting and foraging sites of great
 knots (Calidris tenuirostris) and bar-tailed godwits (Limosa lapponica) at
 Yalu Jiang Estuary, a critical stopover site for shorebirds in the North
 Yellow Sea. We analysed the energy costs of alarm flights by human
 disturbances and commuting using flight energetic models. Camera trap
 monitoring revealed that 20 of 67 (29.9%) roosting records at aquaculture
 ponds recorded human disturbance that resulted in alarm flights. Birds
 travelled 2.8 times farther than the optimal commuting distance when
 nearby high-tide roosts were available. Flight energetic models estimated
 that alarm flights and extended commuting resulted in an additional energy
 expenditure of 355.9–902.3 kJ, equivalent to 3–4 days of foraging effort
 based on food intake rates. Synthesis and applications. Foraging sites and
 nearby high-tide roosts are integral habitat components for shorebirds to
 acquire energetic surpluses, especially at migration staging areas. While
 protecting intertidal flats to provide foraging habitats for shorebirds,
 human activities should be minimised and disturbance should be avoided at
 aquaculture sites during the high tide periods of spring tides to provide
 safe roosts for shorebirds. Artificial roost structures (floating roosts,
 roost islands, etc.,) could also be an effective solution for providing
 additional roosting habitats for shorebirds.
description: # README for Dataset of 'A lack of suitable roosts increases the
 threat of intertidal foraging habitat loss to migratory shorebirds'.
 There is one file for each species (i.e., great knot and bar-tailed
 godwit) studied in this research, in the names of
 "*movement_data_great_knot. csv*" and
 "*movement_data_bar-tailed godwit.csv*", respectively. The
 abbreviation of variables in the file: * f_time: foraging time of the
 individual according to tracking data, the format used for all date/time
 variables are shown in YYYY-MM-DD HH:MM:SS. * f_lon: the longitute of
 foraging area of the individual according to tracking data * f_lat: the
 latitute of foraging area of the individual according to tracking data *
 f_tide: Annotations showing tidal conditions. One hour before the lowest
 tide height within a tidal cycle (l_1); the lowest tide height time within
 a tidal cycle (l0); one hour after the lowest tide height within a tidal
 cycle (l1) * r_time: roosting time of the individual according to tracking
 data * r_lon: the longitute of roosting site of the individual according
 to tracking data * r_lat: the latitute of roosting site of the individual
 according to tracking data * r_tide: Annotations showing tidal conditions.
 One hour before the highest tide height within a tidal cycle (h_1); the
 highest tide height time within a tidal cycle (h0); one hour after the
 highest tide height within a tidal cycle (h1) * highesttide: highest tidal
 height within a single tidal period, shown in centimetres. * Dawn: dawn
 time of the roosting site location * Dusk: dusk time of the roosting site
 location * r_Light: day/night cycle of the roosting period. Daytime was
 defined as the period from dawn to dusk, while nighttime was defined as
 the period from dusk to the following dawn in the study area. * dist: the
 actual commuting distances, shown in metres. * predist_f: the shortest
 commuting distances, shown in metres. --- * THE END ---