Meisen Wood: September Slips By

Ringers:  CS and EB

Sound: various

Temp: from 6C to 34C

September has rapidly slipped by, again. We are amazed, each year, how fast September’s time gracefully slides from the heat of summer to Keats’s season of ‘mellow fruitfulness’. September is a fluid intermezzo between summer and autumn; guests of summer depart and pass through, guests of winter begin to arrive.  The Blackcap’s song fades into migratory tac-tac calls, the Chiffchaff’s onomatopoeic calls are uttered less and less and then are gone to be replaced by the the pink-pink calls of Chaffinch.  This passage of birds is partially reflected in our ringing totals.

Species	Ringed	Re-trapped	Total
Blackbird	4	1	5
Blackcap	6	0	6
Blue Tit	85	26	111
Bullfinch	2	0	2
Chaffinch	1	0	1
Chiffchaff	4	1	5
Coal Tit	20	3	23
Crested Tit	1	1	2
Dunnock	16	2	18
Firecrest	14	0	14
G S Woodpecker	0	2	2
Goldcrest	6	0	6
Great Tit	241	95	336
Greenfinch	0	1	1
Jay	2	0	2
Marsh Tit	6	6	12
Nuthatch	10	10	20
Robin	18	1	19
Short T Treecreeper	8	2	10
Song Thrush	1	0	1
Spotted Flycatcher	1	0	1
Wren	0	1	1
Total	446	152	598

Not shown in the table is that the totals are dominated by juvenile birds, reflecting a productive breeding season in most of the captured passerine species.  From ringing Great Tit, Blue Tit, Pied Flycatcher and Nuthatch pulli in our nest boxes we know that these species had a good breeding season, locally at least, as our figures were our best to date.    

The Coal Tit and Short-toed Treecreeper numbers are the best September figures we have had.  All the Coal Tits were juveniles and certainly represent juvenile dispersal (that is the movement of juveniles away from their natal area into new areas and probably new territories).  This conclusion is backed by the German Migration Atlas which states that most German adult breeders are sedentary with recoveries greater than 10km virtually unknown.  Though a caveat here is that in September and October, in some years, large numbers of juvenile Coal Tits arrive in Germany from the Baltic States – did any of the captured Coal Tits originate from that area of Europe?   

The Short-toed Treecreeper figures probably reflect juvenile dispersal, though adult – juvenile differentiation is difficult after post-juvenile moult is completed.  Ten newly ringed Nuthatches probably reflect post juvenile dispersal too.  Most of the re-trap Nuthatches were adults which we know from our ringing records are territory-holding local birds; they were frequently caught in close proximity to the juveniles thus a possible hypothesis is: the adults were escorting/chasing the dispersing juveniles off their territory.

Fourteen Firecrests through the month is a typical figure for us.  These miniature birds, but a few centimetres long and weighing a tad over five grams, migrate through here in early autumn.  A Firecrest ringed by us was controlled on the Channel Islands some kilometres distant.  No retraps of this species was semi pleasing too as through the spring and summer we have been frequently capturing two males, of two breeding pairs.  Firecrests are frequently in the vanguard of Goldcrest migration; will that be the case this year?

 

With the Great Tit and Blue Tit figures conclusions are more difficult to make and potentially complex.  They probably reflect a genuine mix of dispersal, partial migration and full migration but more on this in a later piece.

Considered caution is a cognitive skill that ringers exercise in relation to such aspects of ringing as: exactly how to extract each bird from the net; identification of a species that is rarely captured; assigning age and sex to an individual; and initially deciding if a re-trapped bird could in fact be a control. 

At one point during the month we were both hesitant as to whether, or not, we had a control Marsh Tit.  Tentatively we concluded that it was a bird with one of our early ring sequences.  The computer said we were correct.  The Marsh Tit was the twenty-ninth bird we ringed in our first ever ringing session here in February 2015.  Further this was its first recapture event; yes, that stimulates several questions but no explanations I’m afraid.  Back in 2015 this bird was aged as an adult meaning this individual is at least six years old.  From ringing studies the oldest German Marsh Tit was 11 years of age. 

Extracting Blue Tits can sometimes be awkward.  But in one of this month’s sessions an easy looking extraction proved to be otherwise: legs freed, wings freed so the remaining few net strands should just slip over the bird’s head and voila - that would be that, but that was not happening.  Careful examination of the bird’s nuchal nape band revealed a goliath of a tick around which several net strands were wrapped.  A judicious cutting of these strands completed the bird’s extraction.  Back at the ringing table the tick was removed and its measurements taken: length 14mm, width 6.5mm and weight 0.1g; it made a satisfying pop when destroyed.

Ticks are common parasites on birds here.  We particularly encounter them on Great Tits, Blue Tits, Chaffinches, Greenfinch and Blackbirds; we record their numbers and location.  Our ringing kit includes forceps for their removal and destruction.  This is partially for the health of the birds but also has a component of self preservation: we don’t want ticks in our garden, or at least only in low numbers.  We frequently find them on ourselves and given that they are vectors of a few nasty diseases we have no qualms in eliminating them. 

Caution needs to be exercised too when extracting garrulous Jays who can inflict pain and draw blood from a ringer’s fingers.  Each autumn we catch a few of these colourful corvids: this September one adult and one juvenile.  In late summer, early autumn we watch Jays with bulging crops excavate shallow depressions, with a few savage blows from their stout bills,

into which they then regurgitate an acorn.  We watch the red squirrels bury acorns too. Research indicates that both species remember where they have buried their treasure ready for consumption during the food scarce times of winter.  They may remember the location of some but by means all the acorns.  An annual spring task is plucking oak saplings from the meadow – this year that was over 300 freshly germinated oaks and maples.  Our plucking, like much of conservation work, prevents succession and our meadow becoming a wood. Though within the wider wood this means the oaks benefit through this method of seed dispersal. 

This year the acorn crop is much less than last year’s when there had been a super abundance of acorns.  This acorn deficit probably explains the near constant movement of Jays over Meisen Wood and along the Teutonburger Hills we have been witnessing this September.  On fine days there has been a clear and distinct migration of Jays flying from ESE to WNW.  CS on five mornings watched for an hour, those birds flying over our restricted view of the hills, his total was 771 Jays.  So the final total will have been huge.  Migration watch points north of here and in the Netherlands have recorded numbers into the thousands which suggests a major failure of their acorn food source somewhere and probably over a large area too.  The migrant Jays were flying at a greater height with a purposeful direction, compared to the lower flying local acorn hunter-gatherers.  They passed over in loose squadrons: 10 here, 17 there, then 39 over there but it was a constant passage just like September is a constant connection between seasons.

Meisen Wood: The Young Ones

Nets: 124m

Sound: None

Weather: 9C to 23C some cloud with light wind

Ringers:  CS and EB

Spring, a most anticipated season, has raced by and is essentially over.  Evidence for this was apparent when we opened the nets to a much diminished dawn chorus; volume down, duration shortened and reduced participants in the choral ensemble.  The day’s excellent, well above average, catch presented the explanation: seventy-two of the birds caught were juveniles.  Many choristers of previous dawns have nearly completed their breeding efforts so have no need to advertise themselves and proclaim their territories. 

Species	Ringed	Re-trapped	Total
Blackbird	1	1	2
Blackcap	2		2
Blue Tit	12	3	15
Chiffchaff	1		1
Crested Tit	6	2	8
Dunnock	1		1
G S Woodpecker	7	7	14
Great Tit	6	20	26
Greenfinch	2		2
Hawfinch	2		2
Marsh Tit	5	1	6
Nuthatch	2		2
Pied Flycatcher	1	5	6
Robin		2	2
Song Thrush	1		1
Total	49	41	90

The numbers are above average for several reasons.  Most of the captures came from the nets close to a derelict fountain whose shallow basin we keep topped up with water, a definite attraction in dry woodland; currently the wood is scented by that delightful fragrance particular to pine in prolonged dry periods.  Also we have kept two small feeders going.  This is a partial response to a documentary featuring a well known German naturalist who suggested year round bird feeding as a means, in a minor way, to compensate for the lack of food in the wider environment, a negative consequence of Germany’s intense agro-forestry industries. This is a point that almost certainly applies to many other nations too.

Of particular note is the number of Great Spotted Woodpeckers: the day’s figures included six new juveniles sporting bright red crown feathers.  So far this month we have ringed eleven juvenile Great Spots; and two new adults.  The day’s re-traps included three of those new juveniles one of which had started post-juv moult; moult in these birds is something we are looking forward to monitoring and given the woodpeckers’ tendency for regular re-trapping will hopefully bring some clarity (for us) to moult, and subsequent aging, in this species.

It has certainly been a good year, locally at least, for breeding tits.  All the newly ringed Blue Tits were juveniles – with a wonderful yellow flush through their faces.  And the three re-trapped Blue Tit were birds we had ringed in boxes in the middle of May.  Similarly the new Great Tits were all juveniles and all but two of the re-traps were birds we’d ringed in the last month at various nest boxes.  One of the re-trapped adult Great Tits had been ringed as a nestling in 2016.  This was not quite the oldest bird of the day, that sobriquet went to a Robin originally ringed earlier in 2016. 

Frequently tits are caught as part of a Tit flock and we were delighted to find in the day’s fourth net round a mixed flock of tits that included six Crested Tit and five Marsh Tits.  All the Marsh Tit were juveniles and included one that had been ringed a few weeks back.  Five of the Crested Tits were new juveniles with an adult male which had been ringed in early 2017.  Catching this chirpy crew of Crested Tits was special as our efforts in providing nest boxes for this species have totally failed (so far), but it is pleasing to know they are succeeding somewhere out there in the woods.

Contrary to the morning’s pattern, the two Hawfinches were adults: a male and a female.  The male Hawfinch’s chin feathers were distinctly marked, like a Spanish marquis’ beard.  He had a cloacal protuberance, just; and she a poorly demarcated brood patch: breeding or not breeding that is the question?

Not shown in the table are six more nestling Pied Flycatchers, bringing this year’s total for nestling to forty-two.  With three more boxes with nestlings to ring later in the week this year’s total will be the largest number of Pied Flycatcher nestlings we have ringed in Meisen Wood – so far.  Surprisingly we have never caught a recently fledged nestling and in this respect we differ from much of the published literature.  Numerous Pied Flycatcher studies indicate that fledglings remain in their natal area for up to forty-five days.  The ones we ring seem to fledge and depart.  Though some of those studies reported catching fledglings at distances between 2 and 10km form the natal site; um, 10km to us would be a control.  And the Pied Flys do seem to be departing: when opening the nets we are often accompanied by the warning chip-chip call of adult Pied Flycatchers as we walk through the wood, there were fewer today.

Mist netting is a sampling technique and an inherent variable in any such scientific technique is that some species’ numbers will be skewed, or absent.  Today there were three absentees.  Firecrests were excitedly twittering for most of the morning in the boughs above our ringing table, a ringed male with his fluorescent orange crest most evident, feeding some youngsters (no crests yet). They numbered ten or eleven birds though these miniscule birds are difficult to count in the canopy’s thick foliage.  During the extraction of the aforementioned tit flock a group of Long-tailed Tits deftly avoided the net; this group of some ten individuals included some juveniles too.  Also a small flock of seven crossbills flew over.  These are sporadic visitors to the wood and occasionally come down to net level to drink at the fountain on hot days – to dream the dream; and even better would there be some re-traps from previous visits? 

Wendover CES4 – 3rd June 2019

560 ft of nets in 6 rides.
Nets open 03:49 – 9:49

Weather: Wind light, Rain none, Cloud scattered. 

	New	Retraps	Total
Blackbird	2 (2 x J)	2	4
Blackcap	3 (1 x J)	2	5
Blue Tit	13 (8 x J)		13
Bullfinch	1	1	2
Chiffchaff	3 (3 x J)		3
Dunnock	6 (6 x J)	4	10
Great Tit	2 (2 x J)		2
Robin	7 (7 x J)	3 (2 x J)	10
Song Thrush	3 (1 x J)	2	5
Whitethroat		1	1
Total	40	15	55

An above average catch for CES#4 with the total of 55 comparing with a historical mean of 41 (range 21-62).  Good contributions of juveniles from the resident species of Blue tits, Dunnocks and Robins.  Also the first juvenile Blackcaps and Chiffchaffs.

Ringers Adam, Pete + Christine as scribe.