Avon BTO

Friday, May 30, 2008

Breeding season so far

A brief summary of the tetrad and Roving records inpout so far . There are some 50 paper forms not included.
There are returns for 17 10km squares ( not ST37), and the number of species reflects the number of tetrads surveyed. 146 species have been seen, with an average of 68. 99 of them were possible breeding species (of which 58 have been confirmed as breeding in at least one square).ST57 has 70 btreeding species, ST58 69. 12 species have been proved in every square, a further 10 in 16/17, and 19 in only one square. It is important that birds that are not yet breeding (?Little Egret ? Siskin) or that have ceased to breed (? Redshank, ?Snipe ? Wheatear ?Redstart) are not put in the possible breeders (ie observed in possible breeding habitat) unless you are pretty sure that are breeding.

One point checking through the records. Occasionally observers say they have recorded for Two hours, but only enter totals for a single hour. This creates problems, because this survey is designed to be compararble fwith the last breeding survey which only asked for ONE hour to be spent in a tetrad twice- but the recording was presence absence not counting. Because the total species seen increases with time spent, and the requirement to count increases the time needed, the First hour species list will be compared with the last breeding Atlas- but the two hours together can be compared with this winter Atlas.

Please enter all first counts that have been recorded, and good luck with the second ones.

Tuesday, May 27, 2008

Bad weather

What a dreadful bank holiday- and from the records it looks as if some 60 tetrads were going to be done. Please try to complete them by May 31st, but records made on Sunday June 1st would count for the first survey- better do it then than wreck this year's breeding season.

Breeding status. At present rather a small proportion of species seen have had evidence that confirms breeding. It is not easy to do this during tetrad a tetrad survey, and it would help if everyone remembered to put in Roving Records for any recent fledglings, or other good evidence- Feeding young (FF) visiting a nest site (ON) etc.- Starlings have just fledged for instance, but are started to move around rapidly. House Sparrow entering nest holes counts as ON (occupied nest). Swifts screaming around a building is D for Display.

And when you do second visit try to improve on the evidence you got from the first.

Friday, May 23, 2008

Winter totals

At last I have some provisional totals for the winter survey.
844 hours were spent in 237 tetrads (some paper forms have yet to be entered) and 227941 birds counted at a rate of 270 an hour. 176 species were recorded, the largest number, 119 in ST58. ST55 had the highest density of birds, at 491/hr, but mainly because only 8 tetrads were surveyed ( the figure for ST77 with 3 tetrads was even higher). The most frequent species were Starling (rate 38/hr) Wood Pigeon (22/hr) Black-headed Gull (21/hr), then Redwing (17/hr)
The biggest changes since the last winter Atlas (25 years ago) were increases of over 200% for GO, LT, Li, PH and R and falls of more than 50% for FP, RO, BH, L. and SD. SG came close with 48% fall.
45 Little Egrets were counted as were 128 Ravens, and 27 Peregrines, and just five Dippers.
When Ive done a write up I will make it available to anyone interested.
Meanwhile Last chance for the first breeding season survey!

Wednesday, May 21, 2008

Ten days to go

There are 73 tetrads that need to be covered in the next ten days, unless some observers have done the first breeding season survey but not sent the records down the line.
I just hope the weather is good.
At long last I am able to access the records from last winter, but checking them is a slow process, and I will send round a note to all as soon as I have got all the tetrad data checked. The process of checking the Roving records and material from birdtrack will probably take more time. The ovwerwhelming mass of records that I have seen so far follow a very clear and consistent pattern, but i will be checking one or two records that surprised me.
Now that birds are fledging Roving records of recently fledged birds are a key to proving breeding, and it is important to keep notes of any that you see and send them in. It is worth checking the Square Summaries list to see what the highest breeding status recorded is.

Saturday, May 03, 2008

Summer at last

April was a normal month (unlike last year) and leafing has been late. Some 50 tetrads have been recorded on line so far, so most people are opting for a May survey. Two points have come up recently; Do record a breeding status for every species you see, even if its just preence in suitable breeding habitat. If you are sure a species is NOT breeding, either because its a migrant or because it is summering, say so. Only leave the breeding status blank if the species is feeding in the square but not breeding ( Like Cormorant, or in most cases Heron).

Secondly always fill in the final page five colonial species count, even when there are NONE. I have left gulls off my April tetrad visits because though present there has been for the most part no sign of nests. Roof nests are impossible to count as part of a tetrad survey, but if you are clear that Gulls are nesting in your tetrad then put in an estimate of the numbers, either after the first visit or the second.
Counts of Rooks nests should go in the first visit.