Urban living influences the nesting success of Darwin’s finches in the Galápagos Islands

1) We examined whether location (urban=PB and non-urban=OG) affected the binary presence or absence of nests with eggs, nests with nestlings, and trash in nest material. We examined the effect of location on hatching and nestling survival trials, where the response variable is a matrix of trials, which are successes and failures, where the number of eggs hatched and nestling fledged per nest represent successes while eggs not hatched and nestling mortalities represent failures, respectively. We also used examined the effect of location along with the proportion of anthropogenic debris in the nest on nestling survival, where nest survival was measured as successes and failures.2) Examined nest survival data over the incubation and nestling periods. Nest fates (binary success=1 or failure=0) over the number of exposure days where each exposure day (obsdays) is a trial. The explanatory variables are covariates of location (urban= PB and non-urban=OG) and proportion of anthropogenic debris in nests which are also weighted by the number of exposure days. Exposure days (obsdays) were calculated using the median of the last day the nest was known active to the last check day when the nest outcome or fate was known. 3) Calculated total person-hours by multiplying the number of hours searched by the number of people searching for each day at both sites (urban and non-urban respectively) across all days of the survey period. We tested survey effort using an independent t-test on total person-hours per day at each site.4) Reproductive activity of nests with eggs, nestlings, and fledgling (where fledging occurred that week) across each week of the study period in non-urban (OG) and urban (PB) sampling areas.1) 本研究探究了生境类型（城市生境记为PB，非城市生境记为OG）对三类巢况的二元存在/缺失状态的影响：有卵巢、有雏鸟巢以及巢材中存在垃圾的巢。同时探究了生境类型对孵化与雏鸟存活试验的影响，该试验的响应变量为成败二元试验矩阵：以每巢孵化出的卵数与成功出飞的雏鸟数作为成功结局，以未孵化的卵数与雏鸟死亡数作为失败结局。此外本研究还分析了生境类型与巢内人为碎屑（anthropogenic debris）占比对雏鸟存活的影响，其中雏鸟存活以成败二元指标进行衡量。2) 本研究分析了孵化期与育雏期的巢存活数据。巢结局以二元指标记录：成功记为1，失败记为0，数据以暴露天数（exposure days，下文简称obsdays）为单位，每个暴露天数视为一次试验。解释变量为生境类型（城市生境记为PB，非城市生境记为OG）与巢内人为碎屑占比，上述变量均按暴露天数进行加权。暴露天数的计算方式为：以巢已知仍处于活跃状态的最后一日，至获知巢结局的最后核查日之间的中位数。3) 本研究计算了总人时（person-hours）：在整个调查周期内，将每日的搜索时长与搜索人数相乘，分别得到城市与非城市两类样地的单日总人时。随后采用独立样本t检验，对两类样地的单日总人时进行比较，以分析调查投入强度的差异。4) 本研究统计了非城市（OG）与城市（PB）采样区域内，研究周期每周的各类巢繁殖活动情况：含卵巢、有雏鸟巢以及当周实现雏鸟出飞的巢。