Territorial duration of Spring Chiffchaff males

Accurate daily recording and positional plotting of male warblers, allows the opportunity to make interesting comparisons in changing arrival patterns and also to determine the number of migrants passing through a particular site or area from year to year.

Warbler arrivals in the area, is something I have recorded since 1998. I soon realised that most migrant warbler counts are probably under-estimated (if even carried out away from breeding surveys) and I base this on my records of male Chiffchaff, Willow Warbler and Blackcap.



Territorial duration of male Chiffchaffs in Spring 1998   Territorial duration in Spring 1998 of Chiffchaff (red) Willow Warbler (blue) Blackcap (yellow) and Whitethroat (brown)
The year's first three Chiffchaff males to hold territory (not including brief hedgerow migrants) have all returned to the same sites. These have been at High Trees (1 male) and Hare Hill Wood (2 males) Whether these are the same birds remains uncertain, but it's likely they are and is probably no coincidence, that these two sites also offer perfect Chiffchaff habitat, both being wooded and with a thick under-storey. When these two sites are fully occupied, later arrivals seem forced to establish territories in less suitable habitats, unless a previously occupied territory is vacated by a male unsuccessful in attracting a female. Most other sites in the area to hold singing males are usually dense and overgrown areas of scrub, large gardens or small Willow copses.

Male Chiffchaffs sing almost daily in territory (each one in the area, being checked daily for continued presence) Territories can be occupied for a day, but more often than not, for up to a week or longer. This obviously depends on the male's ability to attract of a female, but a Chiffchaff singing in one spot on April 3rd, may not be the same one singing there a few days or a week later. I have also noted this feature among male Willow Warblers and Blackcaps, but it is less frequent within male Whitethroats (whose hedgerow habitat requirements are more common) and this shows well in the above graph.

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