Buzzard distribution question

[Lemars]

I'd be pleased if anyone could comment on something I noted on a trip north last week. I traveled from near Bordeaux, France to St Malo along the autoroute and couldn't fail to notice how many birds of prey there were en route.
There has always been a stretch of road where it has been possible to see all manner (and I'd know what they all were if I weren't whizzing past them) of BOP, but this time I decided to while the time away by doing a count of those I could clearly identify.

From Bordeaux to Nantes, I counted 31 buzzards - all within a matter of metres from the road. This is a distance of about 130 miles. It could have been assumed that some of them were pairs, judging by the distance from each other.

Further up, on the stretch from Nantes to St Malo and a similar distance, I saw only 2 buzzards.

The land is fairly flat throughout the trip. Agricultural land diminishes further north, which I appreciate might account for the difference, but could anyone comment on such a hugely diverse number - and with such a distinct cut-off point ? Does anything like this happen in the UK ? I've no previous experience of buzzard-counting !!

Sorry to introduce a clearly non-British question, but I found it an interesting observation and wondered if anyone could comment.

C

[paulinemiller10]

I often find birds of prey sitting or flying around roads, they have learned they can get an easy meal by waiting for an animal or bird to get run over, and they risk the same fate playing chicken trying to eat their meal, so more road kill if they are unlucky, so a good place to hunt. Pauline.

[Dogghound]

The number of variables which could cause this make it a very challenging question to answer. Clearly habitat is going to be a major player not just with regards to hunting but also with regards to roosting and nesting. Levels of persecution could influence it, levels of mortality due to habitat quality, how quickly a population has recovered due to historic decline i.e. due to pesticide use. Buzzards can be quite communal in winter and can group up at rich feeding sites too.

Perhaps the most likely explaination is the time of day or weather. Buzzards like other birds have times of high activity and low activity during the day. i.e. on days or times of day with low cloud cover, low wind and low precipitation buzzards are most active, typically mid-late morning, so as your journey advanced conditions may have changed, even less noticable ones.

[poschiavanus]

The current data in the French Winter Bird Atlas do not show any significant differences between the two areas you mention: - www.atlas-ornitho.fr. Note that atlas data are incomplete so absence of a dot needs to be cross-checked against the dot map of surveyed areas (for instance data are missing for most of Brittany).

Nor are there major differences in landuse immediately North and South of Nantes, as shown by the links to OpenStreetMap which conveniently shows the European CORINE landuse data for France.

Taken together I'd think these data support Dogghound's explanation.

[Lemars]

Morning one and all and thank you for your replies.

I was about to write to you yesterday, Doghound, to thank you for your idea about the time of day - which I'd not really considered - when the further reply arrived from Poschiavanus.

I've been doing that trip a few times a year for 12 years and have been racking my brains to determine if I always pass that section at about the same time of day. I must admit that it would work out approximately the same time, most of the time. Not always, but it's possible that I've not noticed the numbers at other times of day because they've simply not been around. It's just been a general observation in the past.

I'm not the only one who has noticed either - others who do the trip have remarked on the heavy BoP population of that area. Of course, they might well be heading for the same ferry, so that covers that too. Other times have been at night - which makes it a little more difficult !

I'm going to set a posse onto this now. I shall ask others to note the times of their trips and do a count and I shall do it again myself - next time.

By the way, Poschiavanus, thank you for the LPO link. I've used the LPO site on many occasions and managed to avoid (somehow) that particular facility - interesting, but I wish they'd made it a little more precise. I'll be looking again.
Once again - thanks to all.

C

[Dogghound]

Remember to record weather conditions and time of year, as well as time of day.

[Lemars]

Will do - thanks Doghound

C

[basquesteve]

Originally Posted by poschiavanus

The current data in the French Winter Bird Atlas do not show any significant differences between the two areas you mention: - www.atlas-ornitho.fr. Note that atlas data are incomplete so absence of a dot needs to be cross-checked against the dot map of surveyed areas (for instance data are missing for most of Brittany).

Nor are there major differences in landuse immediately North and South of Nantes, as shown by the links to OpenStreetMap which conveniently shows the European CORINE landuse data for France.

Taken together I'd think these data support Dogghound's explanation.

Hi

I am one of the contributors to the ornitho atlas I am lucky I can log on every day with observations directly but only those of us in the green departments are able too hence the lack of observations in parts of France of many species and numbers

[fairplay]

I'd be interested to know if the Buzzard is responsible for displacing the Kestrel as the most common BOP to be seen above our main roads.
I'm pleased that they are becoming more and more common in Suffolk, but hopefully not at the expense of the smaller Kestrel.
But yes, that is a very interesting observation about the sudden drop off in numbers whilst travelling in France and will I'm sure, be of some relevance to the UK.

Neil.