Wetlands are rich in biodiversity, but globally threatened. After a long period of regional extirpation, beavers have recently returned to many European areas and are now restoring wetlands. The beaver is remarkable regarding the large impacts it has not only on individual species but on entire communities and ecosystems. In fact, beavers are referred to as ‘ecosystem engineers’.The facilitative effect of the beaver Castor canadensis on a waterbird community of seven species of waders and ducks in boreal ponds was studied by using the before–after control–impact method (BACI) and analysing the effect of the duration of flooding. The before–after setting could be used since beavers had caused disturbance by flooding several forest ponds during the course of this long‐term study (1988–2009). The study took place in southern Finland, where waterbirds were surveyed four times during the breeding season.The number of waterbird species per pond per year was significantly higher during beaver inundation than before beaver activity, as was the waterbird abundance per survey. Changes were negligible in the controls. The numbers of all seven species increased during flooding, although the increase was significant in only three species. Common teal Anas crecca and green sandpiper Tringa ochropus showed the most positive numerical response to flooding. Mallard Anas platyrhynchos and wigeon Anas penelope were new species entering the duck guild in the flooded wetlands. The beneficial effect of the flood lasted the whole period of inundation, although the most substantial increase in species number appeared during the first two years of flooding.The beaver acted as a whole‐community facilitator for waterbirds. It was inferred from previous studies that this was done by modifying the habitat to make it more productive and structurally favourable. It is concluded that favouring beavers is a worthwhile tool in restoring wetlands to promote waterbird communities. Copyright © 2014 John Wiley & Sons, Ltd.

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1. Boreal forest lakes are normally considered stable environments, but from a duck's point of view, both resource abundance and habitat quality in the lakes may differ from 1 year to another. Duck species differ in their flexibility to respond to variation in environmental factors, such as habitat quality, habitat variability and weather. Anas crecca, the common teal, has been suggested to be a species that can readily colonise newly formed habitat. 2. We studied the effect of habitat quality (invertebrate food resources, amount of spring flood, beaver flood abundance, predation pressure), weather (temperature, precipitation, timing of ice breakup) and pair abundance on breeding success of teal at the landscape scale in Southern Finland. We used 20 years of data (1989-2008) from a study area consisting of 50 lakes. This is typical boreal breeding area for the teal, whose population size is markedly variable. We express breeding success as number of broods in two different age classes. 3. The number of broods in both age classes was explained well by habitat quality, but different variables seem to operate during different phases of the breeding season. Increases in abundance of breeding pairs and of food led to increased production of younger broods. Habitat factors including food and flood abundance were the most important predictors for older broods, which are the more influential in terms of recruitment. These factors manifested in an age-specific manner, highlighting the importance of comprehensive breeding time surveys of boreal breeding ducks to understand variation in their recruitment. 4. Our research underlines the importance of high-quality habitats for breeding teal populations in the boreal forest landscape. The existence of these habitats depends substantially on human actions, such as managing beaver populations and preserving seasonal pond habitats.

European populations of many ground-nesting farmland birds have declined in recent decades. Increases in predator populations and nest predation may play an important role in this decline, along with habitat loss. However, the role of various predators has often remained unclear. We conducted a study with artificial nests and wildlife cameras (n = 104) in agricultural landscapes during 2015-2016 in South Finland. Our trials formed a 400-m wide gradient from forest to field. The aim of our study was to monitor nest survival and nest predators in a spatial and temporal scale. We tested the effect of distance to the forest and nest visibility to nest predation. During an 8-day period, 39.4% of the artificial nests were predated. Fifty percent of the predators were birds, 40% mammals, and 10% remained unknown. The three dominant predators of our artificial nests were the raccoon dog (Nyctereutes procyonoides) with 11 nests and the hooded crow (Corvus corone cornix) and the magpie (Pica pica) with 10 depredated nests each. Our analysis indicates that avian predators preyed upon nests in open fields further away from the forest edge, whereas mammalian predation concentrated closer to the forest edge. Predation occurred more likely at the beginning of the survey and nest survival increased as days passed. Our study highlights the efficiency of using wildlife camera traps in nest predation studies. We also suggest that the ongoing expansion of alien predators across Europe may have a greater impact on ground-nesting bird populations than previously anticipated.