A lack of suitable roosts increases the threat of intertidal foraging habitat loss to migratory shorebirds

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 dista..., , # 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 trac...,

中途停歇地潮间带觅食生境的丧失是诸多迁徙鸻鹬类种群数量下降的首要诱因。然而，高潮位休憩地（high-tide roosts）的缺失会加剧这一负面影响：其会增加鸻鹬类因警戒飞行所消耗的能量，同时拉长觅食地与休憩地间的往返通勤距离，而在时间紧张的春季中途停歇期间，这类影响的量化程度极低。

本研究于北黄海鸻鹬类关键中途停歇地——鸭绿江口（Yalu Jiang Estuary），利用红外触发相机（camera traps）监测休憩地的警戒飞行行为，并追踪了大滨鹬（Calidris tenuirostris）与斑尾塍鹬（Limosa lapponica）在觅食地与休憩地间的往返通勤轨迹。本研究借助飞行能量模型，分析了人为干扰引发的警戒飞行以及往返通勤的能量消耗成本。

红外触发相机监测结果显示，在67条水产养殖塘休憩记录中，有20条（占比29.9%）记录到人为干扰引发了警戒飞行。鸟类的实际通勤距离较最优通勤距离远2.8倍……# 数据集《适宜休憩地缺失加剧潮间带觅食生境丧失对迁徙鸻鹬类的威胁》说明文档

本研究涉及的两个物种分别对应一个数据文件，文件名称依次为`*movement_data_great_knot.csv*`与`*movement_data_bar-tailed godwit.csv*`。

文件内变量缩写说明如下：
* `f_time`：基于追踪数据得到的个体觅食时长，所有日期/时间变量的格式均为`YYYY-MM-DD HH:MM:SS`。
* `f_lon`：基于追踪数据得到的个体觅食区经度。
* `f_lat`：基于追踪数据得到的个体觅食区纬度。
* `f_tide`：潮汐状态标注，包括：潮汐周期内低潮位前1小时（l_1）、潮汐周期内低潮位时刻（l0）、潮汐周期内低潮位后1小时（l1）。
* `r_time`：基于追踪数据得到的个体休憩时长……