Data from: Parrots consume sodium-rich palms in the sodium-deprived landscape of the Western Amazon Basin

Herbivorous animals face shortages of different minerals in different geographic areas. In the Amazon basin, sodium is often limiting, driving herbivores to seek supplemental sources. In the lowlands of the western Amazon basin, parrots commonly consume sodium-rich soils at clay licks but lick use varies widely among species and to date, parrots in the region have not been reported consuming other supplemental sodium sources. We document 11 species of psittacines consuming sodium-rich leaves and trunks of Attalea butyracea palms growing on sodium-rich soils in lowland Peru. Consumed palms had more sodium and less potassium than uneaten A. butyracea palms and other palm species in the area. Among A. butyracea palm parts, sodium and Na:K ratios were highest in trunks (consumed by parrots in 91% of the 721 foraging bouts recorded) and lowest in leaves (consumed in only 14% of foraging bouts). The low potassium and high Na:K ratio suggest that birds may be seeking not just any sodium sources, but those low in potassium, as potassium is known to exacerbate dietary sodium shortages. Use of the palms and species’ abundances in the study area were not correlated. Instead, parrot species that consumed palms the most were those that use relatively few traditional soil clay licks. This finding suggests that parrot species in the region have fundamental differences in preferred strategies for obtaining supplemental sodium and may help explain documented interspecific differences in geophagy. .植食性动物在不同地理区域会遭遇不同类型的矿物质缺乏问题。亚马逊盆地内，钠元素常为限制性营养物质，驱使植食性动物寻求补充性钠源。在西亚马逊盆地的低地地带，鹦鹉通常会在黏土舔食点（clay licks）摄取富含钠的土壤，但不同物种对舔食点的利用差异显著；截至目前，该区域尚未有鹦鹉摄取其他补充性钠源的报道。我们在秘鲁低地地区记录到11种鹦鹉类（psittacines）取食生长于富钠土壤中的巴蒂亚棕（Attalea butyracea）的富含钠的叶片与树干。被取食的巴蒂亚棕个体，其钠含量高于该区域内未被取食的同种群个体以及其他棕榈物种，而钾含量则更低。在巴蒂亚棕的各组织部位中，树干的钠含量与钠钾比最高——在记录的721次觅食事件中，91%的事件涉及鹦鹉取食树干；叶片的钠含量与钠钾比则最低，仅14%的觅食事件涉及叶片取食。较低的钾含量与较高的钠钾比表明，鹦鹉并非单纯寻找任意钠源，而是偏好钾含量较低的钠源——已知钾会加剧膳食中的钠缺乏状况。鹦鹉对巴蒂亚棕的利用频次与该区域内鹦鹉物种的种群丰度并无相关性。与之相反，取食巴蒂亚棕频次最高的鹦鹉物种，恰恰是那些较少利用传统黏土舔食点的类群。这一发现表明，该区域不同鹦鹉物种在获取补充性钠源的偏好策略上存在本质差异，或有助于解释已被报道的不同物种间食土行为（geophagy）的种间差异。