Background: The ideal habitat use of waterbirds can be considered to be fixed, but current habitat use depends on environmental conditions, especially those of food characteristics, considered crucial to their use of habitats. Understanding how waterbirds respond to variation in food availability at degraded wetland sites and change their habitat use patterns over spatial and temporal scales should direct future conservation planning. The objectives of this study were to identify these spatial-temporal foraging habitat use patterns of Hooded Cranes (Grus monacha) and their relationship with food characteristics in the severely degraded wetlands of the Shengjin and Caizi lakes along with the Yangtze River floodplain. Methods: We investigated the changes in food characteristics, relative abundance and density of Hooded Cranes in various habitat types across three winter periods from November 2012 to April 2013. We examined the effect of these winter periods and habitat types on the pattern of use by the cranes and explored the relationship between these patterns and food characteristics using linear regression. Results: The food characteristics and habitat use clearly changed over spatial-temporal scales. In the early and mid-winter periods, the most abundant, accessible and frequented food resources were found in paddy fields, while in the late period the more abundant food were available in meadows, which then replaced the paddy fields. There were fewer effects of winter periods, habitat types and their interactions on habitat use patterns except for the effect of habitat types on the relative abundance, determined as a function of food abundance, but independent of food depth and sediment permeability. Conclusions: In response to the degradation and loss of lake wetlands, the cranes shifted their habitat use patterns by making tradeoffs between food abundance and accessibility over spatial-temporal scales that facilitated their survival in the mosaic of these lake wetlands.

Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012–13 and 2013–14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain.

Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wetlands, which are prone to parasite infection, thus monitoring the diversity of parasites is important for sound wetland management and protection of this species. Methods: From November 2012 to April 2013, we collected 821 fresh faecal samples from the three lakes (Poyang, Caizi and Shengjin Lake) in the lower and middle Yangtze River floodplain, and detected with saturated brine floating and centrifugal sedimentation methods. Parasite eggs were quantified with a modified McMaster's counting method.