[John Cantelo]

I was interested to read in the current edition of 'British Birds' that the linear trend for HB spring records (86-01) rises from just under 25 to just below 75 (ie x3). How far I wonder is this attributable to an actual increase in occurences here in spring - and thus reflecting a similar increase in breeding pairs - or a greater awareness of observers? My suspicion is more the former than the later. Leaving this aside, how good an indication is overall trends in spring to increasing population? Given the notorious secrecy of breeding HBs could this be a better guide to population trends than surveys in breeding season?
John Cantelo

[Jane Turner]

Its all those birds in Northumbria

[Andrew Rowlands]

Hi John,

We know that they have increased in number over the last twenty years or so. This has been related by dedicated fieldworkers spending many long days in the 'right?' breeding habitat.

Many 'birders' would not want to put in similars hours from mid-April to Mid-June, hoping to find a migration 'hot-spot' for Honey's. If we had a plan that would cover enough ground with enough observers, I'm sure we would get a very good idea of the population size. (2 birders per linear mile or so of the Southern and Eastern coastline should do it!).

I think the current 'targetted' approach is a better way of estimating breeding pairs in the areas that can be covered (another half-dozen fieldworkers per county would make a big difference). In the latter part of Spring there is no way of knowing whether a 'fly-by' Honey is a local breeder or a wandering pre-breeder (say 3-5 year old) or a Continental wanderer.

I have spent some time watching an area here in Wales where there appears to be a small non-breeding population. Some of these birds may breed elsewhere locally, but it may be that the local breeding population is close to saturation point; we know so little!

I don't think that we should rely on sightings away from potential breeding areas to make a population estimate; we have no idea how far they would roam under normal conditions, one bird may be reported from several widely spaced locations. Watching over likely woodlands throughout the country, backed up by two or three serious studies into their breeding requirements should be a better approach; and we will learn a lot more than just numbers.

What birds in Northumbria, Jane?

Andy.

[John Cantelo]

Point taken, Andy. However, in terms of plotting general trends, rather than specific population figures, I suspect that numbers seen in spring, if one could factor in observer bias, would be useful. The proportion of "passing"/non-breeding birds rather than established breeders in the UK, would, presumably, be a fairly constant proportion over time. Essentailly what I'm driving at is if spring records increase (or decrease) significantly over time it would be a good indicator of trends. I've certainly spent enough time watching suitable/known HB habitat without a sighting to know just how elusive the species can be. The other factor which encourages the belief that any increase in the UK is genuine is the marked increase just over the Channel. Any Birder based in SE England desperate for increased experience of the species could take advantage of the current ease with which one can nip over to France. Ah, yes Jane, I believe they spell "Honey" c-o-m-m-o-n in Northumbria! John

[CJW]

Now then, now then, don't start all that again.

[Jane Turner]

For what its worth, the spring totals over Hoylake for the last 20 years...of constant effort watching are.
0,0,0,0,0,0,0,0,0,0
0,0,0,0,0,0,0,0,0,0 !

[Andrew Rowlands]

John,

If we were discussing a small passerine that returned to breed in its' first year; then spring counts would be a good indicator.

Honey Buzzards, as far as I understand them, do not return until their second or subsequent years. There has been some continental research that suggests they may not breed until their seventh year!

This would indicate that relying on Spring counts to assesss their population (breeding sucess), may be far behind actual occurences; e.g. a Spring 'dip' in numbers one year may indicate a poor succession of breeding seasons around a decade previously!

If we are to give these birds a good chance of retaining even their current status then we should be looking for sponsorship to study them at their breeding sites. The man hours that have been spent in the last decade or two need to be augmented by more hi-tech studies on their habits during the time they are in Britain. Only when we understand them , are we able to sustain any requirements they may have.

CJW - start what again?

Andy.

[Andrew Rowlands]

Just bringing this one back to the top; I feel I'm missing something....

Andy.