Causes of change

The availability of suitably structured habitat is important and lack of this may have contributed to the decline, possibly through a decrease in nest survival, although evidence for this is based largely on one site, and analysis of data from six other areas concluded that changes in woodland structure were unlikely to be the main driver of population change. This species being a long-distance migrant, problems on its wintering grounds should not be ruled out.

Further information on causes of change

A detailed, eight-year study in Thetford Forest conducted by Burton (2009) provides good evidence that there was a significant decrease in daily nest survival during the chick stage and that overall nesting success was lowest in clearfells and recently planted stands. Overall nesting success appeared to be determined at the habitat scale, and Burton suggested that this may have been because the broad differences in cover between habitats affected the likelihood of nest predation (the main cause of nest failure). Charman et al. (2009) also found that Tree Pipits have high failure rates at the chick stage and implicate predation. It should be noted that records from Thetford Forest, in southeast England, probably contribute over half the nest records for this species each year; thus these trends may not be representative of the UK as a whole. Research by Mallord et al. (2016) found no evidence that changes in woodland structure affected populations in six study areas in the west of the UK.

This species prefers open ground within woodlands and upland grazed woods lacking understorey, and also occupies clearfells, restocks, new plantations, heaths and commons where trees provide songposts (Fuller 1995, Burton 2007, Charman et al. 2009). The species' decline has been greatest in lowland England, particularly in the wider countryside in woodland and common land (Gibbons et al. 1993) and, accordingly, several authors have proposed that the population decline may be linked to the changing forest structure as new plantations mature, and the reduced management of lowland woods (Fuller et al. 2005, Amar et al. 2006, Charman et al. 2009). Data provided by the Repeat Woodland Bird Survey (RWBS) gives reliable evidence that sub-canopy vegetation increased markedly in almost all regions covered between the 1980s and the early 2000s and analyses found that declines of Tree Pipit occurred in woods with higher maximum tree height and increased foliage (Amar et al. 2006, Smart et al. 2007). Fuller & Moreton (1987) and Burton (2007) provide evidence, respectively, for associations with young coppice and, within coniferous plantations, for young restocks, and a disassociation with closed-canopy woodlands. Amar et al. (2006) state that the lack of new plantations and restocks in southern Britain may have contributed to the decline of this species, although specific analyses providing evidence for this were lacking. They also found that Tree Pipit declined more in sites with more tracks, suggesting disturbance can be an issue (Amar et al. 2006, Smart et al. 2007). Burgess et al. (2015) agree that declining availability of young coniferous woodland contributed to Tree Pipit population decline in England. Targeted management, such as the provision of large blocks of habitat and the retention of mature trees for use as songposts, was found to be beneficial (Burton 2007).

In upland habitats, Fuller et al. (2006) provided evidence showing that both overgrazing and agricultural abandonment of marginal habitats may have detrimental effects on Tree Pipits.

Hewson et al. (2007) analysed the Repeat Woodland Bird Survey and BBS/CBC data and found declines in all of the seven long-distance migrant species considered, including Tree Pipit. Thus, although specific evidence relating to factors operating on the wintering grounds is lacking, these cannot be ruled out as causes of population decline.

Information about conservation actions

The strong decline which occurred in the 1990s is possibly linked to changes in woodland structure, although the evidence for this is contradictory (see Causes of Change section, above). Tree Pipits prefer young coppice or restocks and hence rotational management over large forest areas may be needed to ensure that optimal habitat continues to be available on an ongoing basis. Targeted management, such as the provision of large blocks of habitat and the retention of mature trees for use as song posts, was found to be beneficial in Thetford Forest in East Anglia, with the retention of trees enabling the species to use newly cleared areas immediately rather than waiting a few years until new trees were tall enough to be used as song posts (Burton 2007).

There is also evidence that disturbance can be an issue (Amar et al. 2006; Smart et al. 2007); hence actions to reduce disturbance should also be considered, such as limiting or preventing access to key sites or by focusing recreational activity towards specific areas (e.g. by targeted placement of car parks).