Bearded Tit query. (1 Viewer)

[Cornish Chough]

Despite asking several experienced local birders I have never had a definitive answer to this question:-

Why are Bearded Tit's not seen at Marazion Marsh?

You would think the large expanse of reedbeds would be ideal habitat yet sightings are rare, why is this?

I look forward to some interesting replies!

 

[Samuel Perfect]

Hi Cornish Chough,

Good question :t: Since no-one has replied yet I thought I might come up with a possible reason. I would argue that the current range limitations on the species and the fact that it does not migrate or disperse large distances would be the fundamental reason as to why they haven't been seen at Marazion yet. Although the habitat seems to be ideal for the species, the fact that it is rather distant from any other currently occupied habitat may be the key factor (not sure to be honest how close the nearest breeding population are to Marazion). I believe this is an example case where the equilibrium model of biogeography can be applied. Apologies for the complicated term, it basically states that distance between a population of X species (in this case Bearded Tits) and its suitable habitat, know as an "islands" (in this case suitable reedbeds) has so far resulted in the lack of occurrences of the species. On the other hand species where the reedbed is closer to a breeding population or the reedbed is larger and has the potential to host a new immigrant species, there is a greater probability of their occurrence. Of course, this same theory could apply to most species where limitations on dispersal have limited the number of sightings in any given suitable habitat.

Also looking forward to reading some more possible explanations,

Cheers,
Samuel

 

[Samuel Perfect]

A little less scientific answer this time. Could simply be a case of observers not connecting with the species although I personally would believe this is not the case as the marsh tends to be fairly well covered.

 

[Cornish Chough]

An interesting theory! I would guess that the nearest habitat to Marazion occupied by Bearded Tit's could well be the Somerset Levels!? I have seen them on visits to Ham Wall / Shapwick Heath /Westhay but not in great numbers.

I'd have thought that even if Bearded Tit's do not normally travel far from known sites the cold weather of 2010/2011 may have pushed birds further west to milder areas such as Cornwall. People are suggesting this is what has happened with the 2 examples that have recently turned up in a London park.

As you say the Marsh is well covered so I'd think that if there were Bearded Tit's present they would have been seen. It does seem odd to me how they are notable by their absence.

 

[Samuel Perfect]

It may also be a possibility that the reedbed in the marsh is inappropriate for their liking as I have generally seen Bearded Tits in reedbeds growing to twice the height. I'm running out of reasons but I suppose some of the above could all help contribute to the lack of sightings.

Rather frustratingly I was only a few hundred meters away from the very first inner city London B Tits only last week but didn't have the opportunity to see them simply because I was with my family (non-birders) who would have despised me for running off for 2 minutes to see them grrrrrrr :C:C:C

 

[Jacana]

I think it's only a matter of time before they turn up. Despite seemingly being poor at dispersing they can and do find new reed beds (e.g. the colonisation of the NW). It may be that in 5-10 years there are regular reports at Marazion (or Gunwalloe for that matter).

Something tells me that they are also breeding in Devon, maybe around the Exe? Not entirely sure about that though!

 

[Samuel Perfect]

will agree with jacana too. They may be a species restrained by temperature like Dartford Warblers which are more likely to spread further north and west with continued warmer weather since insects are their predominant prey item.

 

[Cornish Chough]

It may also be a possibility that the reedbed in the marsh is inappropriate for their liking as I have generally seen Bearded Tits in reedbeds growing to twice the height. I'm running out of reasons but I suppose some of the above could all help contribute to the lack of sightings.

Rather frustratingly I was only a few hundred meters away from the very first inner city London B Tits only last week but didn't have the opportunity to see them simply because I was with my family (non-birders) who would have despised me for running off for 2 minutes to see them grrrrrrr :C:C:C

The theory you mention of the reedbed being unsuitable is interesting and one I'd like to know more about. Why would the reeds at Marazion be unsuitable? Anyone able to provide more details?

 

[davercox]

Something tells me that they are also breeding in Devon, maybe around the Exe? Not entirely sure about that though!

If they are then someone is doing a good job of keeping quiet about it.
One has turned up on the Exe this winter and caused a fair amount of interest (haven't seen it myself yet).

 

[Jos Stratford]

They may be a species restrained by temperature like Dartford Warblers which are more likely to spread further north and west with continued warmer weather since insects are their predominant prey item.

The slight spanner to this theory being that Bearded Tits (unlike Dartford Warbler) breed up into north-east Europe where winter temperatures are a tad chillly (minus 18 C as I write this, periods down to minus 25 and 30 occur most winters). Here, the birds are highly dispersive and partially migratory.

 

[scoxie]

I think the original question was "why are Bearded Tits not seen at Marazion Marsh?". I'm surprised that no one has mentioned that a small flock was seen several winters ago! They stayed for at least a few days and included males and females. It's true they are by no means regular visitors but they have been seen.

 

[Samuel Perfect]

Thanks scoxie, I only found out yesterday that Bearded Tits had in fact been recorded at Marazion. Since I'm a relative newcomer to Cornwall I'm still learning about past records of birds to the county so bear with me

 

[Dave Parker]

I think the original question was "why are Bearded Tits not seen at Marazion Marsh?". I'm surprised that no one has mentioned that a small flock was seen several winters ago! They stayed for at least a few days and included males and females. It's true they are by no means regular visitors but they have been seen.

Hi Steve et al.
Not sure which flock you are refering to, but up to eight birds were present at Marazion from 21st Oct 2003 to 28th Mar 2004, 10 on 27th Oct 1973, 40 on 22nd Oct 1972 and 22 on 17th Oct 1965. Note the interesting cluster of arrival dates. A clue to their origin may come from a pair of birds trapped at Nanjizal on 27th Oct 2003 that had been ringed in Holland on 14th Sep 2003. To put all these birds in context, in total only c234 birds have been recorded in Cornwall since 1965.
Hope that is of some help.
Dave

 

[John Cantelo]

Contra some statements here that Bearded Tit are disinclined to travel far from established sites, they do wander quite widely. I've seen flocks of 40+ circle up from a reedbed at Stodmarsh and head into the far distance to the east; they can and do cross the North Sea to Holland. Although the first record for Scotland came as recently as 1972, following the discovery of 3 juvs found on the Tay in 1992, a large colony built up at this location (indeed it was the largest in the UK with 250 pairs in 2004!). Although the most recent rare breeding birds survey (2010) did not report confirmed breeding on the Tay (which is evidently hard to access), this does illustrate the species' capacity to move long distances and establish colonies in habitats distant from the core areas if they are suitable. In this context, although distant from colonies around the North Sea, it would not seem impossible that they could appear at Marazion occasionally or might even attempt to colonise the site. Digging though the Birds of Cornwall (1978) I find birds were present on Marazion 13/10/65 - 08/04/66 (max 22 on 17/10) and again in 1972/73 -22/10 - 19/03 (max 42 on 28/10). Birds were also seen in the winters of '73-74 & '74-75. I'm sure those with a more recent reference could fill in the details - I'd be surprised if they haven't turned up if not annually then every few years or so.