Exploring the use of the South African Nest Record Scheme to detect changes in phenology: A case study using four well represented species

Phenological changes are one of the most well recognised responses of organisms to climate change. The ability to detect phenological change often relies on long-term datasets, which are scarce in the global south. As the adaptive capacity of species is highly variable, it is important to improve our understanding of how species in southern hemisphere systems may be responding to climate change through shifts in their annual cycles. Citizen science projects, like bird Nest Record Schemes, offer valuable long-term data, although data quality can pose challenges, affecting their use in research. We investigated the suitability of the South African Nest Record Scheme for estimating lay dates and preliminary exploration of phenological shifts in four well-represented species. Firstly, this study explored the composition of nest records for each species, specifically the proportion of single- to multi-visit cards. Secondly, we explored the accuracy of single-visit cards in estimating lay dat..., We selected 6146 unique record cards from the period 1950-1999 for four common bird species (two passerines and two columbids) from the SANRS, with the most digitally available records at the time of this study. Details of the data and the sample sizes per species are summarised in Table 1. Nest record data were checked row by row for accuracy. Most records gave only a place name and region, so we assigned co-ordinates to each record using Google Earth and Google Maps search engines. Locations were assigned to the nearest plausible central point given the available information on each card. Records were excluded if they contained ambiguous information (missing dates, unclear type of breeding activity, unknown location) or were thought to be a repeat card of a previous nest record. For each species we calculated the start, peak and length of the egg-laying period for both single-visit and multi-visit records using the estimated lay dates. The start of egg-laying was defined as the 5th pe..., , # Exploring the use of the South African Nest Record Scheme to detect changes in phenology: A case study using four well represented species

Dataset DOI: [10.5061/dryad.0000000bz](10.5061/dryad.0000000bz)

## Description of the data and file structure

The dataset contains information from the South African Nest Record Scheme for four bird species. Each row represents an observation from a record card, where cards have multiple visits/observations the card number (cardno) is the same.

The data is in a CSV format. Each species has its own CSV file. The Metadata file will explain each variable/column of the data. This data is part of a greater database, and certain filtering has been applied. This dataset represents only records from South Africa during the years 1950-1999.

## Variable definitions

| Variable | Description ...,

物候变化（phenological changes）是生物对气候变化最广为认知的响应之一。检测物候变化的能力往往依赖长期数据集，而这类数据在全球南方（global south）地区十分匮乏。由于物种的适应能力（adaptive capacity）存在高度异质性，提升我们对南半球（southern hemisphere）生态系统中物种如何通过年周期偏移响应气候变化的认知至关重要。诸如公民科学（citizen science）项目——如鸟类鸟巢记录计划（bird Nest Record Schemes）——可提供宝贵的长期数据，但数据质量问题可能带来挑战，进而影响其在研究中的应用。本研究评估了南非鸟巢记录计划（South African Nest Record Scheme）在估算产卵日期方面的适用性，并对4个样本量充足的常见鸟类物种的物候偏移展开了初步探索。首先，本研究分析了各物类的巢记录构成，重点关注单次到访记录卡与多次到访记录卡的占比；其次，探究了单次到访记录卡在估算产卵日期时的准确性……
本研究从该计划（SANRS，South African Nest Record Scheme的缩写）1950-1999年的馆藏中，筛选出6146份针对4种常见鸟类（2种雀形目鸟类和2种鸠鸽类）的唯一记录卡，为研究时数字化可得的最多记录。各物类的数据详情与样本量汇总于表1。研究人员逐行核查巢记录数据以确保准确性。多数记录仅提供地名与区域信息，因此我们借助谷歌地球（Google Earth）与谷歌地图（Google Maps）搜索引擎为每份记录分配坐标。基于每张记录卡的可用信息，将点位匹配至最近的合理中心点。若记录存在信息模糊（缺失日期、繁殖活动类型不明、位置未知）或被判定为重复的过往巢记录，则予以剔除。针对各物类，我们利用估算的产卵日期，分别计算单次到访与多次到访记录的产卵期起始、峰值与时长。产卵期起始被定义为第5个百分……

# 探索南非鸟巢记录计划在物候变化检测中的应用：基于4个常见鸟类物种的案例研究

数据集DOI：10.5061/dryad.0000000bz

## 数据与文件结构说明
本数据集包含源自南非鸟巢记录计划的4种鸟类相关信息。每条数据对应一张记录卡的一次观测结果；若一张记录卡包含多次到访/观测，则其记录编号（cardno）保持一致。
数据采用CSV格式存储，每种鸟类对应一份独立的CSV文件。元数据文件将对数据的各变量/列进行详细说明。本数据隶属于更大的数据库，并经过了特定筛选流程。本数据集仅涵盖1950年至1999年期间南非境内的巢记录。

## 变量定义
| 变量名 | 描述 ...,