Congregations of rodent-eating birds during flood irrigation of crops exploit novel prey pulses and potentially provide pest control services

In California’s Central Valley, we have observed large congregations of rodent-eating birds, including wading birds, raptors, and Corvids- hunting for rodent prey during flood irrigation of alfalfa fields. A pilot study in 9 fields revealed a mean of 23.7 rodent-eating birds, and a maximum of 102 birds, hunting simultaneously in a field. We observed a total of 293 rodent prey captures in 570 minutes of monitoring and calculated a mean of 1.03 rodent prey captures per hour of avian hunting effort. We believe these initial observations provide insights into the responses of rodent-eating birds to an intensive farming practice that echoes natural fluctuations in surface water. We propose four testable hypotheses for others exploring the role of irrigation practices for carnivorous birds-  1) Rodent-eating birds use social and environmental cues to exploit prey during short-term flood irrigation events; 2) Rodents make up a larger proportion of the diet of Ardeidae species in regions t..., We identified 9 alfalfa fields that utilized flood irrigation in Yolo County, in California’s Central Valley. We visited fields during irrigation and visited each site 1-4 times in May-July in 2017 or 2018.  Each visit consisted of a 30-minute period split into six consecutive 5-minute observation intervals. Within each interval, we counted any ‘rodent-eating bird’: species that include rodent prey in their diet, including raptors, wading birds, and corvids. We observed foraging of birds present in fields and counted all rodents consumed by birds in the same time interval. Rodent species were not discerned between, however fossorial rodents commonly impacted by flood irrigation in this region are Botta’s pocket gopher  and California vole.  Only rodents that were sighted being consumed were counted. Wading birds held prey items in their beaks prior to swallowing them, whereas birds of prey including B. swainsoni generally appeared to consume prey items by holding them on ..., , # Data for Congregations of rodent-eating birds during flood irrigation of crops exploit novel prey pulses and potentially provide pest control services

[https://doi.org/10.5061/dryad.jm63xsjn9](https://doi.org/10.5061/dryad.jm63xsjn9)

## Description of the data and file structure

### Files and variables

#### File: Data\_for\_Kross\_et\_al\_2025\_Ornithological\_Applications.xlsx

**Description:** 

##### Variables

* Data includes the site ID, the date of the observations, the temperature (C), percent sky obscured by clouds, wind on a 0-5 scale, the height of the crop, the start and end time of each 5-minute observation period, and then a column for each of the rodent-eating bird species we commonly observed and a column for the number of rodent prey items that were observed caught by each bird species within the 5 minute interval. We use 4-letter codes to represent the bird species. There are also columns for the total number of rodent-eating birds observed, the total number of pr...

在加利福尼亚中央谷，我们观测到大量食啮齿鸟类（rodent-eating birds）聚集于苜蓿田的漫灌（flood irrigation）时段捕食啮齿类猎物，该类群涵盖涉禽（wading birds）、猛禽（raptors）及鸦科（Corvids）鸟类。一项针对9块田地的试点研究显示，单块田地中同时活动的食啮齿鸟类平均为23.7只，最高可达102只。在总计570分钟的监测时长内，我们共记录到293次啮齿类猎物捕获事件，经计算，鸟类捕食活动每小时平均可捕获1.03只啮齿类猎物。我们认为，上述初步观测结果揭示了食啮齿鸟类对一种集约化农业耕作方式的响应——该耕作方式可模拟地表水的自然波动。我们提出四项可检验的假说，供后续研究者探索漫灌耕作对肉食性鸟类的作用：1）食啮齿鸟类可借助社会与环境线索，在短期漫灌事件中追踪猎物；2）在特定区域，啮齿类在鹭科（Ardeidae）物种的食谱中占比更高……。我们在加利福尼亚中央谷的优洛县（Yolo County）共筛选出9块采用漫灌方式的苜蓿田。我们于2017年或2018年的5月至7月期间，在漫灌时段对每个样地进行1至4次实地造访。每次造访包含30分钟的观测过程，被划分为连续6个5分钟的观测区间。在每个区间内，我们统计所有“食啮齿鸟类”——即食谱中包含啮齿类猎物的鸟类类群，包括猛禽、涉禽与鸦科鸟类。我们观测样地内鸟类的觅食行为，并统计同一区间内被鸟类捕食的所有啮齿类猎物数量。本研究未对啮齿类物种进行区分，但本区域受漫灌影响的常见地下啮齿类为博塔囊鼠（Botta’s pocket gopher）与加州田鼠（California vole）。仅统计被观测到正被鸟类捕食的啮齿类个体。涉禽会在吞咽猎物前将其衔于喙中，而包括B. swainsoni在内的猛禽通常会按住猎物后再行进食。

# 作物漫灌期间食啮齿鸟类聚集：利用新型猎物脉冲并潜在提供虫害防控服务
[https://doi.org/10.5061/dryad.jm63xsjn9](https://doi.org/10.5061/dryad.jm63xsjn9)

## 数据与文件结构说明
### 文件与变量
#### 文件：Data_for_Kross_et_al_2025_Ornithological_Applications.xlsx
**描述：**
##### 变量
数据集包含样地ID、观测日期、气温（℃）、天空云量占比、0至5级风力分级、作物高度、每个5分钟观测时段的开始与结束时间，随后为我们常见观测到的食啮齿鸟类物种的四字母编码列，以及对应5分钟时段内各鸟类物种捕获的啮齿类猎物数量列。我们采用四字母编码表征鸟类物种。此外还包含食啮齿鸟类总观测数量列、啮齿类猎物总捕获数量列（原文未完整展示）……