Thrush species are rarely parasitized by cuckoos, but many have a strong egg recognition ability. To date, there is a limited understanding of the relationship between host egg rejection and cuckoo parasitism rate.

By using egg experiments in the field, we compared egg rejection between two non-parasitized potential host species and two parasitized hosts of cuckoos in the same region.

The White-bellied Redstart (Luscinia phoenicuroides), a host of the Common Cuckoo (Cuculus canorus), rejected 66.6% of blue model eggs; the Elliot's Laughingthrush (Trochalopteron elliotii), a host of the Large Hawk Cuckoo (Hierococcyx sparverioides), rejected 25% of blue model eggs and 46.1% of white model eggs; and the Chestnut Thrush (Turdus rubrocanus) and the Chinese Thrush (T. mupinensis), in which cuckoo parasitism has not been recorded, rejected 41.1 and 83.3% of blue model eggs, respectively. There were no significant differences in the egg rejection among them, although the Chinese Thrush showed the highest rate of egg rejection.

This study indicates that the egg recognition ability of cuckoo hosts has no correlation with the actual parasitism rate of cuckoos. We suggest that the egg recognition ability of the two potential host species may have been retained from a parasitic history with the cuckoo, while the two common host species have developed their egg rejection abilities due to current parasitism pressure. In addition, our study highlights the importance of the multi- cuckoo parasite system for better understanding the selection pressure of parasitism on the evolution of host egg recognition abilities.

Nestling discrimination and feeding habits during brooding are important factors affecting host selection of parasitic birds. Some host birds can avoid being parasitized by discriminating their nestlings or feeding food not suitable for parasitic nestlings. Thrushes are common medium-sized birds with widespread distribution and an open nesting habit, but they are rarely parasitized. It remains controversial whether this is due to feeding habits and/or nestling discrimination.

In this study, we tested the nestling discrimination ability and feeding habits of Chestnut Thrushes (Turdus rubrocanus) which is distributed in China's multi-cuckoo parasitism system. Their nestling discriminability and feeding habits during brooding were studied by cross-fostering experiments and video recording to examine evolutionary restrictions on nestling discrimination and whether feeding habits are consistent with the growth of cuckoo nestlings.

Our results indicate that Chestnut Thrushes using earthworms as the main brooding food can feed and maintain cuckoo nestlings and show no nestling discrimination.

The present study confirms that feeding habits cannot be regarded as the main factor affecting Chestnut Thrushes being rarely parasitized by cuckoos but suggests that egg rejection is likely to limit the evolution of nestling discrimination in thrushes.

Incubating birds must balance the conflict between thermal needs of the developing embryos and their self-maintenance needs for energy. The Chinese Grouse (Tetrastes sewerzowi) lives in high mountain conifer forests and faces energy stress, cold environment, and predation pressure. Females might adjust incubation rhythm to adapt to these constraints.

Two methods were used to investigate egg laying and incubation pattern of the Chinese Grouse; 25 nests were monitored by data loggers and 12 nests by infrared video cameras.

Female Chinese Grouses usually laid an egg every 2 days. The incubation period was 28-31 days. Overall incubation constancy for Chinese Grouse was 93%. The females took 5.0 recesses per day and 34% of all 1696 recesses were taken in the crepuscular period. The average recess duration was 20.3 min. Females took more and shorter recesses in the latter part of incubation. The females who allocated more time to foraging had a higher reproductive success.

Probably due to its high egg/body mass ratio, the Chinese Grouse has a long laying interval of 49 h. We suggest that, due to energy stress, females have relatively more recesses and they increase the number of recesses as incubation progresses. To compensate for the embryos' thermal needs, they extend the incubation period and shorten the recess duration in this cold environment.

Life history traits play critical roles in population survival and evolution. Breeding information should be particularly detailed in order to provide significant insights into the population status and the evolution of other traits. To our knowledge, there is still no information about the breeding biology of Spectacled Parrotbill (Sinosuthora conspicillatus), an endemic parrotbill in China.

We searched the nests, checked all nests found and recorded the information of eggs, nestlings and nest sites of the Spectacled Parrotbill from 2013 to 2015 at Lianhuashan National Nature Reserve in Gansu Province, China.

A total of 16 nests were found. Nest trees were artificial young spruces and honeysuckles. Mean nest height was 0.89 ± 0.47 m (n = 16) above the ground level. All nests were cup-shaped and constructed using leaves, fine strips of barks and grasses by both parents. The mean clutch size was 4.42 ± 0.79 (n = 12). The eggs were oval in pale blue without speckles, and the mean egg mass was 1.25 ± 0.07 g (n = 27). The egg length was 15.56 ± 0.46 mm (n = 27) and the width was 12.46 ± 0.29 mm (n = 27). Incubation period was 13 days and nestling period was 13–14 days. The breeding success rate was 46%, and among those failed nest, 71% were depredated and 29% were deserted.

Detailed life history information about parrotbill is still limited. The breeding biology of Spectacled Parrotbill reported in the present study should be helpful for further research about population, breeding behavior and conservation of this bird.

The habitat features of breeding territory have important adaptive significance for the survival and reproduction of territory holders. The Chinese Grouse (Tetrastes sewerzowi) is a rare and endemic species with relatively small distribution range and decreasing population trend. It is important to elucidate breeding territory habitat requirements of the Chinese Grouse for habitat management and conservation actions.

Using radio-telemetry and field observations, we determined the core areas of 65 breeding territories of males. Two to three samples were selected in each core breeding territory as used sites and compared with nearby sites with no grouse occurrence using logistic regression.

Our model showed a high accuracy in prediction of core breeding territory used by males, which preferred stands with more small deciduous trees (0.5 m ≤ height < 5 m), more small willow trees (Salix spp., 0.5 m ≤ height < 5 m), greater willow cover, and greater herb cover. The number of small willow trees had the greatest influence on males' core breeding territory selection. Dense shrubs were also chosen compared with unused sites. Tall conifer trees was an important determinant in the distribution of Chinese Grouse at the landscape scale, and was relatively important in the univariate model, but not included in our final multivariable model.

Male Chinese Grouse established territories at sites with abundant food resources. At the landscape scale, the Chinese Grouse occurred in alpine conifer forest. At the territory scale, small willow trees had the most important effect on males' core breeding territory selection. We suggest that the forest gaps in dense conifer forest are important for improving the occurrence of willows and facilitating breeding territory establishment for the Chinese Grouse.

The drivers of intraspecific variation in behavioral plasticity are poorly known. A widely held hypothesis is that brain size is positively correlated with behavioral plasticity.

A total of 71 Chestnut Thrushes (Turdus rubrocanus) were caught in the wild population. We quantified behavior plasticity of activity of individuals measured in the same cage across two contexts (common and with a novel object stimulation), using a random regression analysis. We then investigated whether head volume (a proxy for brain size) was associated with behavioral plasticity in activity level using Spearman rank-order correlation.

We found no significant evidence that activity plasticity was associated with relative head volume. There was no sex difference in head volume or in variance in head volume.

We speculate that the absence of an association between brain volume and activity behavior plasticity may result from the inaccuracy of using external skull measurements to estimate brain size, or from a particular part of the brain being responsible for plasticity in activity level.