The webrumble
A brumble in the wrong place

Brumbles are renowned for their adaptable masticatory systems, yet even these highly versatile birds have certain limitations to their adaptations. Current species are mostly folivorous or mixed feeders, lacking any grazing behaviors. Numerous reasons might explain this, with the most significant being competitive exclusion by more specialized graminivorous birds like trenchcrawlers, hoofpoles, terrariders, and the several grazing rodent species.
Given these dietary constraints, it might seem unlikely that any brumble species would adapt to the vast grasslands of the trample steppe. Surprisingly, there is one species thriving in this environment—the webrumble (Fluvirostris palta), a highly derived brumble. Although its diet includes an insignificant portion of graminoids, these birds survive primarily by foraging in the infreqeunt wetlands of the steppe. To adapt to these wet environments, webrumbles have evolved partially webbed feet, aiding in reducing sinking into the mud. Despite not being strong swimmers, they can dive up to 5 meters deep in search of aquatic plants and algae, similar to the behavior observed in the Holocenic moose and the now-extinct coose.
Webrumbles feed on twigs of doorpeas and cancerthorns shrubs, which become more common in wetlands due to reduced grazing impacts by large mammals, which generally favor drier subregions of the trample steppe. Webrumbles are like beduin, wandering in a large unsuitable environment in search of oasis, which are in their cases the rivers and bogs. Although uncommon because of the dry environment, these wet habitats create a continuum in the steppe, allowing webrumbles to flourish. The species is more frequent near mountain ranges compared to open plains, where the hydrographic network is smaller but denser.

Similar to other rostrids, webrumbles possess a wing pouch used for nurturing their eggs and chicks. The reproduction period typically begins in April, at the onset of the cold season. However, embryo development is not immediate. Females can effectively "freeze" embryos' development, a reproductive strategy called embryonic diapause; although this method was already observed in the avian world, the webrumble is the first ever bird to do this while embryo are still inside the first part of the uterus, before the primitive-streak stages and egg shell deposition start. This delayed process could be an adaptation to improve fitness, since during early spring males might be weaker and unable to produce sufficient sperm for fertilization after the winter season. Simultaneously, the fresh spring food intake ensures adequate energy for females to produce enough yolk for egg development and chick rising. Another reason for this evolutionary trait could be facilitating reproduction, due to the solitary behaviour of this bird: it's easier to find a partner in autumn, when webrumbles densities reach its maximum, instead of early spring, after the harsh (and often deadly) winter. 

Winter proves challenging for webrumbles as their primary food sources—wetlands—largely freeze and become inaccessible. In the absence of fresh food, they resort to feeding on herbaceous plants and mosses. Due to these ecological limitations, webrumbles often disappear from the trample steppe when large and efficient grazers, like hoofpoles and terrariders, appear.