When I made a vague Twitter enquiry about our migratory friends arriving, heralding the start of our summer, I was intrigued to see there is something of a definite pattern emerging:

(I have left the Twitter names of the contributors so you can follow them if you want)

@jwtwits
Numbers in Spanish hills near Malaga are definitely dropping. Keep a look out…

@rossimilburn
Swallows flying around garden of the Falcon pub at Hatton  Easter Monday Warwickshire

@christiaan_may
Swallows in. No swifts yet  Shropshire

@petermc0104
 Swifts arrived in last week. They’re on their way! Swallows r also about too! Co.Antrim, NI

@KenHigham
Swallows in spotted 21/04/2014  Lancashire

@Treespers42
Swifts seen passing over yesterday @RSPB_OldMoor Barnsley

@Steveredwolf
Swallows and some sand martins in  but no house martins or swifts yet West Yorks

@Jon_D_Clarke
Swallows in Tomnaverie Stone Circle. Aberdeenshire

@PhilipMillns
Swallow which I tweeted yesterday from Gib point . No Swifts yet. Skegness

@drmtbishop
Swallows in East Lothian

@naturesgreat

Swallows at Claines in on 13th april – aprox 10 days early Worcester

@6_tailed_comet
Swallows here no swifts yet! Notts

@LauraAOwen
Swifts preparing to nest near  this weekend. Lovely! Brecon

@John_Ranson

Swallows around for 3 or 4 weeks. Keeping an ear out for Swifts but none yet Norfolk

@hurst_liz
Swallows seen yesterday near  but no swifts Cambridge

@bertikusmaximus
Swallows around our estate in Gloucester.

@RyanClarkNature
 Swallows but no swifts so far Buckinghamshire

@GillABanks

Swallows are in the Vale of Glamorgan

@MMandyjackson54
Swifts and swallows over Sandy Water Park in  last week so they’re here! Llanelli, S Wales

@BirderChris
Swallows been around in small numbers for a couple of weeks. No swifts yet Lincolnshire

@Skylarkingforu
Swallows  in but not seen any swifts yet Essex

@theleeshore

Swallows yesterday at Wilmington, East Sussex

@WeimaRunner
Swallows / martins seen coming in over the Solent

@amythebirder
Swallows. Also Sand Martins & House Martins Hampshire

@brunc222

Swallows in Wiltshire. More in Hants/Dorset. No swifts but house martins in Devizes

@oldciderhouse
Swallows around #NetherStowey and the #Quantocks Somerset

And I am delighted to say I saw 2 swallows in Marshwood west Dorset yesterday!

So as you can see there is a concentration in from the Midlands to the north of England with less in the south.

Interesting and thank you all very much for your responses!