Farmland birds are declining globally due to anthropogenic activities, with particularly few studies in Asian agricultural landscapes. Various studies have examined the impacts of landscape heterogeneity on farmland bird composition, but few have considered seasonal changes in bird diversity and examined functional feeding guild assemblages. Here, we disentangle the impact of seasonal variation (summer, monsoon, and winter), cropping practice (mixed crop, monocultural-crop, and fallow land), crop type (rice, wheat, maize, sugarcane, and other crops), landscape heterogeneity, and the number of houses and trees on the richness and abundance of farmland birds and their feeding guilds conducted within human-dominated agricultural landscapes of lowland Nepal. We established 116 transects (farmland = 100, forest = 8, and river = 8), and each transect was visited nine times from April 2018 to December 2019, with forests and river transect to test the dissimilarities in bird composition between those habitats and farmlands. We recorded 201 bird species in farmland, 133 in the forest, and 131 in river habitats. Bird composition on farmlands showed more dissimilarity with forest than river transects. We recorded nine globally, and 26 nationally threatened birds in farmlands. Seasonal variation and cropping practice significantly influenced the richness of all farmland birds and resident birds only, whereas species abundances vary by season only. We recorded higher species richness in the winter season and mixed crop fields but greater abundance in the monsoon and monoculture crop fields. Farmland bird richness increased with increasing tree numbers but decreased with increasing house numbers. Sugarcane fields had the highest bird richness within crop species, whereas rice fields had the greatest abundance. Seasons and cropping practice also shaped the assemblages of feeding guilds differently. In the context of increasing crop intensification globally, our study suggests that the governments in this region should encourage farmers to cultivate mixed crops and simultaneously restrict the urbanization of farmlands to protect bird diversity. Seasonality should be factored into analyses aimed at understanding bird diversity in agricultural landscapes.

由于人为活动，全球农田鸟类正在减少，尤其是对亚洲农业景观的研究很少。各种研究已经检查了景观异质性对农田鸟类组成的影响，但很少有人考虑鸟类多样性的季节性变化并检查功能性饲养公会组合。在这里，我们解开了季节变化（夏季、季风和冬季）、种植实践（混合作物、单一作物和休耕地）、作物类型（水稻、小麦、玉米、甘蔗和其他作物）、景观的影响异质性，以及在尼泊尔低地人类主导的农业景观中进行的农田鸟类及其觅食行会的丰富性和丰度的房屋和树木数量。我们建立了 116 个样带（农田 = 100，森林 = 8，河流 = 8），从 2018 年 4 月到 2019 年 12 月，每个样带被访问了 9 次，通过森林和河流样带来测试这些栖息地和农田之间鸟类组成的差异。我们记录了农田中的 201 种鸟类、森林中的 133 种和河流栖息地中的 131 种。农田上的鸟类组成与森林比河流样带表现出更多的差异。我们在全球范围内记录了 9 只，以及 26 只在农田中受到国家威胁的鸟类。季节变化和耕作方式仅显着影响所有农田鸟类和常驻鸟类的丰富度，而物种丰富度仅因季节而异。我们记录到冬季和混合农田的物种丰富度更高，但季风和单一种植农田的丰度更高。农田鸟类丰富度随着树木数量的增加而增加，但随着房屋数量的增加而减少。在农作物中，甘蔗田的鸟类丰富度最高，而稻田的丰富度最高。季节和耕作方式也不同地塑造了喂养行会的组合。在全球作物集约化程度不断提高的背景下，我们的研究表明，该地区政府应鼓励农民种植混合作物，同时限制农田城市化以保护鸟类多样性。应将季节性因素纳入旨在了解农业景观中鸟类多样性的分析中。季节和耕作方式也不同地塑造了喂养行会的组合。在全球作物集约化程度不断提高的背景下，我们的研究表明，该地区政府应鼓励农民种植混合作物，同时限制农田城市化以保护鸟类多样性。应将季节性因素纳入旨在了解农业景观中鸟类多样性的分析中。季节和耕作方式也不同地塑造了喂养行会的组合。在全球作物集约化程度不断提高的背景下，我们的研究表明，该地区政府应鼓励农民种植混合作物，同时限制农田城市化以保护鸟类多样性。应将季节性因素纳入旨在了解农业景观中鸟类多样性的分析中。