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Field choice and breeding of Greylag Geese 7

Field choice in spring and breeding performance of Greylag Gees e Anser anser in southern Sweden. L. Nilsson, M. Green & H. Persson

D epartm ent of Anim al Ecology, University of Lund, Ecology Building, SE-223 62 Lund, Sweden Email: Leif.nilssonOzooekoLlu.se, m artin.green0zooekol.lu.se

S e le ctio n and e x p lo ita tio n of fe e din g are a s by p re - b r e e d in g and n o n ­ b re ed in g Greylag Geese A n s e r an se r, as w e l l as by fa m ilie s , w a s s tud ie d in a b re ed in g area c o n s is tin g of f o u r la ke s in Scania, s o u t h e r n m o s t S w eden, in th e y e a rs 1997-2000. Total p ro d u c tio n of yo u n g in each lake as w e l l as th e b re e d in g p e r f o r m a n c e of n e ck c o lla re d in d iv id u a ls w a s e s ta b lis h e d a n n u a lly , 1985-2000. T his b re e d ing p o p u la tio n in c re a s e d on ave ra ge 15.3% p e r a n n u m , fr o m 93 p a irs in 1985 to 910 p a irs in 2001. The tw o m a in fie ld ty p e s used by p r e - b r e e d in g pairs, m a le s of in c u b a tin g fe m a le s and n o n - b r e e d e r s in flo c k s w e re w i n t e r w h e a t and g ra s s la n d , often s w itc h in g f r o m th e f o r m e r to th e l a t t e r in m id -s e a s o n . A lm o s t a ll fe e din g d u rin g b ro o d - r e a r in g to o k place on p a s tu re s g ra z e d by liv e sto ck o r on a g o lf- c o u r s e . G e n e ra lly in s p rin g , th e ra te s of e x p lo ita tio n w e re b e lo w 300 -4 0 0 goose days ha"1, but ra te s of >1,000 goose days h a ' 1 w e re noted f o r one c e re a l fie ld and tw o g r a s s la n d areas. The ra te s of e x p lo it a ­ tion by f a m ilie s v a rie d m a r k e d ly a m o n g b ro o d - r e a r in g a re a s as w e l l as years, being h ig h e s t a ll t h r o u g h th e s tu d y p e riod on a grazed pastu re, w h e r e it ra n g e d 80 0-1,350 goose days h a '1. In c lu d in g th e u tilis a tio n by n o n -b r e e d e r s , th e a n n u a l e x p lo ita tio n of th is p a s tu re ra n g e d fr o m 1,400 to 2,500 goose days h a 1. At th e o n ly lake w it h o u t g ra z in g by liv e s to c k (since th e m id -1 9 9 0 s ), s ig n ific a n tly f e w e r g o s lin g s s u rv iv e d to fle d g ing th a n at the o t h e r la k e s (45% vs 70%). In d ic a tio n s of d e n s ity - d e p e n d e n t e ffe c ts on th e p ro d u c tiv ity of s m a l l you n g w e r e noted at one of th e lakes (K lo s te rv ik e n ) but n o t at a n o t h e r (Yddingen). M ost likely, th e la ck of any d e n s ity d e p e n d e n t effect, in sp ite of th e v e ry m a r k e d in c re a s e in th e b ree d ing p o p u la tio n d u rin g th e stu d y p e rio d at Yddingen, is th e r e s u lt of access to h ig h ly fe r tiliz e d g ra ss on a g o lf co u rse .

Key W ords: Greylag Goose, breeding resu lt, fie ld choice, Sweden © W ildfow l & Wetlands Trust

W ildfowl [2002] 53: 7-25

8 Field choice and breeding of Greylag Geese

Fitn ess c o n s e q u e n c e s of th e u tilis a ­

Greylag Geese s ta rte d in 1984, as a part

tion of d iffe re n t h a b ita ts w ith d iffe re n t

of a N o rd ic p ro je c t (A nd ersso n e t al.

q u a litie s have been s tu d ie d fo r a n u m ­

2001).

ber

r o l li n g

of

goose

G a u t h ie r

s p e c ie s

1989;

B la c k

(B é d a rd et

al.

&

1991;

The

la k e s

a re

a g ric u ltu ra l

e xtensive

a re a s

s itu a te d

in a

la n d s c a p e

w it h

of c e re a l c ro p s

(ef.

G a u th ie r ef al. 1984; Prop ef al. 1998). In

N ils s o n & P e rsso n 1992, 1998), but also

m o s t cases, th e s e s tu d ie s did not go

in c lu d in g

beyond th e p o p u la tio n level, not lo okin g

lakes.

into h a b ita t s e le c tio n of d iffe re n t in d i­

The

grazed

la k e s

are a s close to the

are

a ll eutrophic, w ith

v id u a ls [but see B la c k ef al. 1991). In

p la n k to n b lo o m s and extensive reeds.

th e Greylag Goose A n s e r anser, N ilsso n

S u it a b le

& P ersson (1994) e s ta b lis h e d m a r k e d

Geese

d iffe re n c e s in b re ed in g p e rf o rm a n c e of

M oreover, Lake F jä llfo ta s jö n has s e v e r­

in divid u als fr o m d iffe re n t lakes situa te d

a l good n e stin g is la n d s and th e r e are

in

a

s m a ll

in

fo r

n e s tin g

a v a ila b le

in

G reylag

a ll

lak e s.

s o u th e rn m o s t

also a fe w is la n d s in Lake Yddingen.

S weden. Young h a tc h e d in th e s e lakes

T h ere are extensive are as of grazed

a lso

p a s tu re s c lose to La ke s Yddingen and

showed

a rea

re e d s are

d iffe r e n c e s

in s u rv iv a l

d u rin g th e fo llo w in g w in t e r and also in

B ö rrin g e s jö n .

t h e i r fu tu re r e c r u it m e n t into th e b re e d ­

only one good gra zin g area fo r g o slin g s

ing p o p u la tio n (N ils so n et al. 1997).

and Lake F jä llfo ta s jö n has fe w s u ita b le

In th is paper, use and e x p lo ita tio n of fe e d in g and

a re a s

f a m ilie s

e s ta b lis h

b ro o d - re a rin g areas. Lake Yddingen is bo rd e red by a g o lf course, giving easy access to large area s w ith h ighly f e r ­

w h e t h e r th e r e

is

tilis e d grass. A ll

b ro o d - re a rin g

c o m p e titio n fo r food b e tw e e n breeding

exception

and n o n -b r e e d in g geese, th e selectio n

La k e

of fe e din g a re a s by n o n -b r e e d in g birds

e ith e r

was

F jä l lf o ta s jö n ,

a ls o

s tu d ie d .

has

p airs

kn o w n bre e din g re s u lts w a s stu die d . In o r d e r to

K lo s te rv ik e n

Geese w ith

by p r e - b r e e d in g of Greylag

Lake

F in a lly ,

d e n s ity -

d e p e n d e n t e ffec ts on th e p ro d u c tio n of young in th is rapidly in c re a s in g p o p u la ­ tion w e re in vestigated.

of th e

g o lf- c o u r s e

F jä llf o ta s jö n , c a tt le

or

areas, w ith w ere

h o rs e s .

g r a z in g

by

th e

and

at

g ra z e d

by

At

L a ke

l iv e s t o c k

ceased in th e m id -9 0 s . L a ke s

K lo s te rv ik e n

and Yddingen

w e re chosen f o r m o re intensive s tu d ie s as they offered p o ss ib ilitie s to m e a s u re

S tu d y Are a

o v e ra ll b ree d ing success. These p a r a ­ m ete rs

The b re e d in g

s tu d y

was

area

c o n d u c te d

w it h

fo u r

in

a

la k e s

(Klosterviken, Börringesjön, Fjällfotasjön and

Yddingen)

s o u th e rn m o s t

in

s o u th w e s t

Sweden

S cania ,

( F ig u r e

1),

w h e r e c a tc h in g and n e ck c o lla rin g of

c o u ld

o n ly

be

s tu d ie d

fo r

in d iv id u a lly m a r k e d geese in th e o th e r lakes, w h e re m o r e extensive s tu d ie s of field choice w e re made.

Field choice and breeding of Greylag Geese 9

F ig u re 1 . Map of the study area showing the four lakes with the main feeding areas in black. Light-shaded = woodland areas. 1. Klosterviken; 2. Börringesjön; 3. Fjällfotasjön; 4. Yddingen. Map of south Sweden showing the general position of the study area inserted.

M ethods

d e p a rtu re

in a u tu m n .

In s p rin g,

th e

stu d y area w a s v isited se ve ra l tim e s a D u rin g

1984.-2000,

551

a d u lt and

week,

w he rea s

o b s e r v a t io n s

w e re

1,632 yo ung Greylag Geese w e re neck

m a d e once o r tw ic e a w e e k d u rin g th e

c o lla re d in th e stu d y area, in th e last

a u tu m n period. O b se rv a tio n s w ith th e

fe w years m a in ly at La ke s K lo ste rv ike n

aim to e s ta b lis h th e b reeding r e s u lts of

and Yddingen [P ersson 2000). R e g u la r

a ll neck c o lla re d b ird s w e re e sp e cially

c h e c k s fo r th e o c c u rr e n c e of m a rk e d

intensive d u rin g th e period fr o m h a tc h ­

in d ivid u a ls w e re m a d e fr o m th e a rr iv a l

ing u n til th e young w e re fledged. The

of th e fir s t geese in s p rin g u n til th e ir

a u tu m n

checks

i n c lu d e d

stag in g are as at th e coast.

im p o rta n t

10 Field choice and breeding of Greylag Geese

A ll Greylags p re s e n t at th e d iffe re n t lak e s w e re co un te d tw o to th re e tim e s

2001). T h erefo re, th e co n ce p t of goose days w a s used u n ifo r m ly in th is study.

a w e e k fr o m t h e i r a r r iv a l in s p rin g u n til

R a in fa ll d u rin g early brood re a rin g

late May. The co u n ts covered a ll feeding

can reduce s u rv iv a l a m o n g g o s lin g s 50% of

rately. For each lake, th e n u m b e r of

th e days d u rin g th e

b re e d ing p airs each y e a r w a s e s ta b ­

w e re e xclu d ed fr o m the c a lc u la tio n s of

lis h e d

as th e

m a x im u m

p a ir c o u n t

before s ta r t of in cu b atio n . D u rin g

re g re s s io n s ti m i n g

h a tch in g

period

(Figure 2). As the exact

of th e

h a tc h in g

p e riod

often

1997-2000, th e d is trib u tio n

va rie s s lig h tly a m o n g sites, the effect of

of geese on d iffe r e n t fie ld s w a s e s ta b ­

ra in fa ll m ig h t v ary a m o n g th e breeding

lished on a ll su rveys in s p rin g . On the

lakes. T his is th e case in th e stu d y area

basis of th e s e o b s e rv a tio n s th e p e r ­

w h e re b re ed in g at Lake Yddingen g e n ­

ce n ta g e fre q u e n c y o f geese on d iffe re n t

e r a l ly

fie ld s and field ty p es w a s e sta b lish e d

Klos te rvik en.

is

e a rlie r

th a n

at

L ake

fo r pairs and unpaired geese, respective­ ly. Exploitation rates (goose days ha'1,

R esults

abbreviated gd ha ') of d iffe re n t fie ld s by geese of d iffe re n t c a te g o rie s w e re c a l ­ c u la te d

by u s in g

b e fo re

Goose num bers

m e n t io n e d

e s tim a t e s and th e n u m b e r of pairs and

W hen th e c o u n ts s ta rte d in 1985,

fo r te n - d a y

th e to t a l b re e din g p o p u la tio n w a s 93

M o st bro o d s at L a ke s K lo stervike n

and 910 p airs in 2001 (Figure 3). The

and Yddingen c o n c e n tr a te d on a fe w

in crease, on average 15.3% p e r a n n u m ,

fee d in g

non-breeders

( e s tim a te s

pairs, in cre a sin g to 710 pairs in 2000

periods).

se a rch e d

w a s not th e s a m e t h r o u g h o u t th e stu dy

s ev e ra l ti m e s a w e e k d u rin g 1985-2000

period. The re w a s a m o re o r less steady

to

incre ase in th e n u m b e r of pairs d u rin g

areas, w h ic h

e s ta b lis h

th e

to t a l

w e re

p ro d u c tio n

of

1997-2000, th e rate of

1985 to 1992, fo llo w e d by five years w ith

e xp lo itation of th e m a in b ro o d - re a rin g

relatively s tab le n u m b e r s of aro u n d 440

a r e a s w a s c a l c u la t e d as g o o s e days

pairs. Then, th e n u m b e r of b reeding

ha 1 f o r a d u lts and young in th e broods

pairs in cre a se d m a r k e d ly again.

young. D u rin g

based on th e a c c u m u la te d brood and

In a d d ition to th e bree d ing

pairs,

young to t a ls fo r th e d iffe re n t re a rin g

flo c k s of n o n -b r e e d in g Greylags w e re

areas. Owing to la rg e d e m a n d s of p r o ­

re g u la rly

tein, g o s lin g s need to c o n s u m e at least

(Figure 4). M a x im u m to t a l c o u n ts fo r

as m u c h food as t h e i r p a re n ts d u ring

th is c a te g o ry ra n g e d be tw ee n 600 and

th e b ro o d - re a rin g p e riod (Massé et at.

800 birds in 1997-1999, and increased

fo u n d

in

th e

s tu d y

area

Field choice and breeding of Greylag Geese 11

2,50 -,

Klosterviken excluding wet years

Young/Pair

2,00

1,50 -

1,00

y = -0,0106x + 2,1379 0,50 -

R2 = 0.43

0,00 40

20

60

80

100

120

140

B reeding pairs

4.00

Yddingen 3,50

♦

♦

♦

3.00 ■

Young/Pair

2.50 -

2,00

♦

-

1.50 -

y = -0,0005x + 2,4179 R2 = 0.004

φ 1,00

♦

■

0,50 · 0,00

·

50

100

150

200

250

300

350

B reeding pairs

Figure 2. Number of young per pair initiating breeding in relation to the number of breeding pairs at Lakes Klosterviken and Yddingen, 1985-2000. Years with extrem e w eather conditions during brood rea r­ ing are not included (see Methodsl.

12 Field choice and breeding of Greylag Geese

1000

-,

1985

1987

1989

1991

1993

1995

1997

1999

2001

Figure 3. N u m b e rs of breeding pairs of Greylag Geese in the study lakes, 1985-2001

Figure 4. Total n u m b e r of non-breedin g Greylag Geese in the study area, in ten -d ay periods durin g the springs of 1997-2000.

Field choice and breeding of Greylag Geese 13

to a b o u t 1,000 birds in 2000. T h e re w a s

Exploitation of feeding areas

a large t u r n o v e r a m o n g th e n o n - b r e e d ­ ers, d e m o n s t ra te d

by re - s ig h t in g s of

n e c k c o lla re d in d iv id u a ls (Leif N ils so n & H akon P ersson, u n p u b lis h e d data). The n o n -b r e e d e r s a rriv e d in th e area d u rin g F e b ru a ry and M arch, to g e t h e r w ith th e b reeders, bu t left in ea rly to m id May to m o u l t e ls e w h e re (N ilsson et

M ost geese at Lakes K lo stervike n and Yddingen w e re fe eding close to the lakes, th e lo n g e st f lig h ts to re g u la rly visited fie ld s being a b o u t 2 k m (Figure

1). S im ila rly, m o s t Greylags at Lake B ö rrin g e s jö n w e re also flying only re la ­ tively s h o r t d is ta n c e s to t h e i r fe eding areas. S o m e w h a t l o n g e r fe eding flig h ts

at. 2 0 0 1 ).

w ere

made

by G re y la g s

fr o m

Lake

F jä llfo ta sjö n, w h e r e th e r e w e re no good

Field choice

fe eding are a s c lose to th e lake. The tw o m a in field ty pe s used by

At Lake

K lo s te rvike n , th e

hig hest

both p re - b re e d in g pairs, m a le s of in c u ­

rate of e xp lo itatio n (1,017 goose days

bating

ha"1) w a s fo un d f o r th e sh o re m e a d o w in

fe m a le s

and

n o n -b r e e d e r s

in

flo c k s w e re w in t e r w h e a t and g r a s s ­

1999 (Table 1). T h is m e a d o w w a s r e g u ­

land (in th e la tte r case in c lu d in g the

la rly fr e q u e n te d in a ll years, esp e cially

g o lf- c o u r s e at Lake Yddingen) (Figure

in th e la t t e r p a rt of th e s p rin g season.

5). Yddingen differed fr o m th e o th e r

In th e e arly p a rt of th e season, th e

lakes as th e g o lf- c o u r s e a cco u n te d fo r

geese m a in ly used w in t e r w h e a t e ith e r

a b o u t 50%, of th e geese. C ere al fie ld s

on fie ld s C o r D close to th e lake, but at

w e re m u c h less used at L ake Yddingen

a s o m e w h a t lo n g e r dista n ce in 1998,

th a n at th e o t h e r lakes.

w h e n both th e s e fie ld s w e re used fo r

Early in th e season, th e geese at

o th e r crops.

B ö rrin g e s jö n

At Lake K lo ste rvik e n, only one fe e d ­

used w in t e r w h e a t f o r 50 -6 0 % of t h e i r

ing area w a s availa ble fo r th e fa m ilie s

La ke s

K lo ste rvik e n

and

feeding. In A p ril, a l m o s t a ll pairs and

(B, Table 2). The t o t a l n u m b e r of goose

m o s t flo ck s, fed on g ra s s la n d at th e se

days ha 1 in th is m e a d o w ranged 190-

lakes,

330 fo r young and 300-1,155 fo r a d u lts

but s o m e

flo c k s

used w in t e r

w h e a t. In May, s o m e flo c k s at Lakes B ö r rin g e s jö n and Yddingen fed on w in te r

(b re ed ers and n o n -b re e d e rs ). A t Lake Yddingen, th e h ig h e s t ra te s

wheat and s o m e on ne w ly sown cereal,

of e x plo itatio n

by n o n -b r e e d e r s w e re

w h e re a s a ll geese at L ake K lo ste rvike n

fou nd fo r a field w it h w in t e r w h e a t in

w e re fo u n d on g ra s sla n d .

2 0 0 0 and a g ra s s la n d along th e sh o re

of the lake in 1998, w h ic h a tta in e d 1,260 and 1,170 goose days ha"1, re spectively

(Table 3). e x p lo it a t io n

G e n e ra lly , w ere

th e

m uch

rates lo w e r

b e lo w 3 00-400 goose days ha '.

of and

1A Field choice and breeding of Greylag Geese

At Lake Yddingen, fa m ilie s used a n u m b e r of d iffe re n t fe eding

g ro u n d s

(Figure 1). The r a te of e x p lo it a t io n

present, th e fa m ilie s fed close to the s h o re

and

in

a

m a r s h la n d .

In

th e

evening and e a rly m o r n in g w ith fe w golf

c ould be e s ta b lis he d at th r e e of th e se

players, th e y used la r g e r p a rts of the

areas: A (a grazed p a s tu re at th e shore)

g o lf course. E xp lo ita tion ra te s fo r f a m i ­

+ U (an open, grazed w o o d la n d), E (the

lies w e re c a lc u la te d fo r the pa rt of the

g o lf-c o u r s e ) and V (a grazed pastu re

g o lf co u rs e

close to a pond). The g o lf co u rse w as

m a r s h la n d , w h e re a s ex p lo ita tio n v a l­

clo se to th e

sh o re

and

only p a rtly used by th e fa m ilie s . D urin g

ues fo r n o n -b r e e d e r s re fe r to th e e ntire

daytim e, w h e n th e r e w e re g o lf players

g o lf course.

Table 1. Exploitation Igoose days h a 1) by all non-breedin g Greylag Geese of different subareas at Lake Klosterviken in spring, 1997-2000. Field types in different years are given in brackets. GR=Grazing area,

EIS=Autumn sown cereals, SS=set aside,

RA=winter rape,

ST=stubble fields, TR=ley fields, VA=mown grass, G0=golf course, M=energy plantation (Salix), BS=grazed forest. Sub-area

Area (ha)

1997

1998

1999

2000

B

15.2

2201GR)

6651GR)

1017IGR)

3391GR)

C (part)

19.5

1241HS)

0(SS)

0IRA)

0(HS)

D

28.3

170(ST)

8IRA)

3031HS)

595ÍHS)

E

12.6

5(GR)

681GR)

4-1 [GR]

143(6 R)

G

27.1

3(GR)

34-ÍGR)

28IGR)

56IGR)

L

8.7

5(GR]

961GR)

1581GR)

259IGR)

N

63.9

OlSS)

45 (VA)

O(SS)

O(HS)

P

76.5

OlTR)

501HS)

0(HS)

OlSS)

Table 2. Exploitation (goose days ha"1) by Greylag Geese of the main brood -rearing area (shore m eadow B), at Lake Kosterviken, 1997-2000. Total area of the shore meadow is 15.2 ha. Total n u m b e r of young and parents in the different years are given in brackets, for c o m ­ parison, the rate of exploitation by non-breedin g Greylags fo r the brood -rearing area is shown both for the w hole spring and fo r the brood -rearing period. 1997

1998

1999

2000

191(88)

205(84)

332(138)

273(111)

83(38)

93(38)

138(58)

126(54)

Whole spring

220

665

1017

339

A pril and May

172

233

844

207

Young Parents A dults w ith o u t family:

Field choice and breeding of Greylag Geese 15

Table 3. Exploitation (goose days ha ') by all non-b re edin g Greylag Geese of different subareas at Lake Yddingen in spring, 1997-2000. Field types (see Table 1] in different years are given in brackets. Sub-area

Area (ha)

1997

1998

1999

2000

A

4.5

9951GR)

1170IGR)

5901GR)

420(GR)

E

110.2

130EGO]

2381G0)

371 (GO)

369(GO)

F

6.9

3451GR)

162.LÊR]

1451GRI

4771GR)

G ‘

13.2

11KGR)

1771GR]

151ÍGR)

3521GR1

H

10.2

264IVA)

3281VA)

237IVA)

3 73 (VA)

K

23.2

147IGR1

97(GR)

256IGR)

163(GR)

R

18.5

34(ST)

200 (VA)

451HS)

100 (VA)

S

18.7

2 (VA)

29 (VA)

11 (VA)

5 (VA)

T

23.2

137(HS)

451HS)

109IHS]

69(HS)

V

12.3

1121GR)

1791GR)

1071GR]

132(GR)

Y

5.5

12(VA)

37(HS)

0IRA)

1260(HS)

The re w e re m a r k e d d iffe re n c e s in th e

ra te

breeding o u tp u t a m o n g th e stu d y lakes

by Greylags

fo u n d by N ils s o n & Persson (1994). The

betw een th e d iffe re n t a re a s at Lake

p ro p o rtio n of s u c c e s s fu l pairs differed

Yddingen

of e x p lo itatio n

(Table 4). The sh o re (A+U)

yield ed th e hig h e st ra te s of e x p lo ita ­

b e tw e e n

th e

la k e s

(F=3.00,

P=0.03,

Table 5). B ro o d s iz e s a ls o d iffe r e d

tion, w ith m o re th a n 1 ,0 0 0 goose days

b etw een th e lakes (F=4.74, P=0.003 fo r

ha "1 f o r young in tw o y e a rs out of four,

s m a l l yo u n g ,

and fo r a d u lts in tw o years. The hig h est

fle d ge d young, Table 5). A verage n u m ­

rate of e x p lo itation w a s noted in 1998,

b e rs

w ith an o ve ra ll rate of >2,500 goose

K lo s te rv ik e n

days

s ig n if ic a n t l y

h a '1. In th e

same

y e a r >1,100

goose days ha "1 w a s noted fo r n o n ­

of

F= 7.92,

s m a ll and

P = 0 .00004 fo r

yo u n g

at

B ö r r in g e s jö n

lo w e r

th a n

at

Lakes w e re L ake

Yddingen (f— 3.64, P=0.000 and f=-2.21,

b re e d e rs in th is area. T h e re w a s an

P=0.028, respectively, Table 5), w h ile

increa se in th e ra te of e xp lo itatio n by

th e r e

Greylags both fo r area E and V but th e re

betw een Lake F jä llfo ta s jö n and Lake

w a s no su ch te n d e n c y over th e fo u r

Yddingen (f=-1.25, P=0.21, Table 5) . The

ye ars fo r area A+U (Table 4).

was

no

s ig n ific a n t

d iffe r e n c e

n u m b e r of fled g e d yo ung w a s s ig n if i­ ca n tly lo w e r at La ke s K lo ste rvik e n and

Breeding perform ance

F jä llfo ta s jö n th an at Lake Yddingen (f=3.21, P=0.01

The lo n g e r se rie s of data now a v a il­ a b le

c o n firm s

th e

d iffe r e n c e s

in

and

f— 4-45, P=0.00001,

Table 5). There was only a n u m eric a l ten-

16 Field choice and breeding of Greylag Geese

Yddingen

i

100 90 80 70 60 50 40

EJGolf course ■ Set-aside CDStubble □Winter Wheat Ξ Grassland

30 20

10 0% Flock

I

Pair

Flock

I

Pair

Flock

I

Flock

Pair

A p ril

March

February

J

Pair

May

100%

90% 80% 70%

|H Stubble □ W inter Wheat j Ü Grassland

60% 50% 40% 30% 20% 10%

0%

Flock

I

Pair

Flock

February

I

Pair

Flock

March

I

Pair

Flock

April

J

Pair

May

B ö rrin g e s jö n

Rape Newly sown ; □ Winter Wheat j § Grassland |

Flock

I

Pair

February

F lock

I March

Pair

F lock

J A p ril

Pair

F lock

I May

P a ir

I J

Figure 5. Field choice of Greylag Geese in flocks and pairs, respectively, in different m onths at Lakes Klosterviken, Börringesjön and Yddingen. Pooled data fo r the years 1997-2000.

Field choice and breedng of Greylag Geese 17

dency fo r Lower n u m b e r s of fle d g lin g s

Due to th e low n u m b e r of Greylag

at Lake B ö rrin g e s jö n (f=-1.68, P=0.09,

Geese

Table 5). W h e re a s 6 8-71 % of th e s m a l l

B ö r rin g e s jö n and F jä llfo ta sjö n , a n n u a l

young survived to fle d g in g in th e th ree

v a riatio n in bre ed in g re s u lt could only

la kes

K lo s te rv ik e n,

Yddingen,

B ö rrin g e s jö n

only 45%

did

so

in

neck

c o l la r e d

in

Lakes

and

be s tu d ie d fo r La k e s K lo s te rv ik e n and

Lake

Yddingen. W h e re a s th e r e w a s no s i g n if­

Fjä llfo ta sjö n (χ?,=84.8, P=0.001 ; Table 5).

ic a n t

d i ffe r e n c e s

in

p ro p o rtio n

of

s u c c e s s fu l pairs at Lake Yddingen over

Table 4. Exploitation (goose days ha'1) by Greylag Geese of the three main brood rearing areas at Lake Yddingen (Figure 2b), 1997-2000. Total n u m b e r of young and parents in the different areas and years are given in brackets. For comparison, the rate of exploitation by no n-b reed ing Greylags of the brood -rearing areas is shown both for the w hole spring and for the brood -rearing period. 1997

1998

1999

2000

Young: A+U

891(151)

1128(188)

645(110)

1087(149)

E

123(191)

159(222)

179(274)

242(297)

V

226(193)

242(87)

435(144)

594(182)

169(58)

236(72)

142(50)

193(54)

E

26(78)

32(86)

37(112)

54(132)

V

4-8(40)

57(42)

77(56)

92(56)

A+U

995

1172

589

424

E

130

238

371

369

V

112

179

107

132

550

316

342

254

E

55

35

156

77

V

88

54

65

86

Parents: A+U

Adu lt s w ith o u t family Whole spring:

A p ril and May: A+U

18 Field choice and breeding of Greylag Geese

Table 5. Com parison of breeding pe rfo rm an ce of Greylag Geese in the study lakes, 19872000 . Klosterv

B örn ng e

Fjällfota

Yddingen

541321)

63(237)

57(147)

69(481)

140

105

68

227

S m a ll young

4.36±2.04

4.71 ±2.65

4.96±2.16

5.43±3.28

Fledged young

2.93+2.27

3.33±2.53

2.18± 2.01

3.89±3.31

68

70

45

71

Per cent successful pairs (>=1 fledged young) Brood sizes [seen w ith s m a l l young and checked fledged young) N

S m a ll young surviving to fledging (%)

Table 6. Fledging success and mean brood sizes in relation to feeding areas of Greylag Goose pairs seen w ith s m a l l young at Lake Yddingen 1997-2000. Feeding area

% with >=

S m a ll young

Fledged young

No. of Families

4.61 ±2.12

1 fledged young Golf course No rth shore

91.0 95.0

3.67±2.60 3.90±2.05

66

4.80+2.13

South shore+pond

89.7

5.70±2.79

4.03±3.14

29

th e

s tu d y

p e rio d

20

(χ213= 17.4-, P=0.18;

and th e n u m b e r of young p e r breeding

Figure 6), th e r e w a s a s ig n ific a n t a n n u ­

a t t e m p t (n u m b e rs of pairs seen at th e

al

s ta r t of th e b re ed in g used as e q uivalen t

v a r ia tio n

fo r

L a ke

K lo s t e r v ik e n

(χ213=31.2, P=0.003; Figure 6).

of th e n u m b e r of bre e d ing a tte m p ts )

For Lake Yddingen, no d iffe re n c e s in

[Figure 2, r=0. 0.65, P=0.02], in d ic atin g

b reeding p e r f o r m a n c e could be e s ta b ­

d e n s ity -d e p e n d e n t e ffe cts on th e p ro ­

lished a m o n g fa m ilie s using th e th ree

d u c tio n of you n g at th is lake. There

d iffe re n t b ro o d - re a rin g area s studied

w e re

(Table 6, x 22=CU 6 , n .s.).

d e p e n d e n t e ffe c ts on th e p ro d u c tiv ity of

For Lake K lo s te rv ik e n th e re w a s a s i g n if ic a n t

n e g a tiv e

c o r r e la t io n

b etw e e n th e n u m b e r of b reeding pairs

no

in d ic a tio n s

of any d e n s ity -

s m a l l young at Lake Yddingen (Figure

2 , r = 0 . 0.06, n.s).

F ie ld c h o ic e and b re e d in g o f G reylag G eese

19

90 η 80 -

■ Y dding en □ K lo s te rv ik

70 60 50 40 30 20

-

10

-

1987 1988

1989

1990

1991

1992 1993

1994

1995

1996

1997

1998

1999

2000

Figure 6 . Reproductive success (percentage of breeding a tte m p ts re su lts in at least one fledgling) at Lakes Klosterviken and Yddingen, 1987-2000.

Discussion

(T h e r k ild s e n

&

Madsen

observed s h ift fr o m Geese g e n e ra lly s w itc h fr o m a s i m ­

2000).

The

w in t e r w h e a t to

gra ss w a s pro b a bly g overned by a c o n ­

ple c a r b o h y d r a t e - r ic h diet in a u tu m n

ti n u a l

and e a rly w i n t e r to m o r e p ro t e in - ric h

young leaves of w i n t e r c e re a ls (Groot

d e c lin e

of

p ro te in

c o n te n t

of

&

1989). D iffe re n ce s in s o il c h a r a c t e r i s ­

A n k n e y 1992; B ro m le y & Ja rv is 1993;

tic s and v a rie tie s of c e re als gro w n give

v e g e ta t io n Budeau

in

s p rin g

et at.

1991;

( A lis a u s k a s G a u t h ie r

1993;

rise to large w it h in - f ie l d d iffe re n c e s in

M ain g u y & T h o m a s 1985; Owen 1980;

g ro w th ra te of s e e d lin g s in th e stu d y

Prevett et at. 1985). The tw o m a in field

area. As a result, w i n t e r c e re a l fie ld s

ty p e s

reach

e x p lo ite d

by

fe e d in g

G reylag

th e

s tage w h e n

Geese in late w in t e r and s p rin g in this

u n s u i t a b le

study, as w e ll as in o th e r p a rts of the

geese at d iffe re n t tim e s . The t im in g of

b reeding ran ge (P ersson 2002), w e re

s h ifts f r o m one fie ld type to a n o th e r is

w in te r o ff e r in g

c e re a ls

and

le aves

in

fe e d in g

g ro u n d s

fo r

both

largely conditioned by a ir te m p e ra tu r e

p ro te in

(P rins & Ydenberg 1985, T h e rk ild s e n &

g ra s s la n d ,

ric h

as

th e y b e co m e

Madsen 2000).

20 Field choice and breeding of Greylag Geese

Th ere is co n s id e ra b le lit e ra tu r e on

f o r Taiga Bean Geese A n s e r fabalis on

e x plo itatio n ra te s o f d iffe re n t field types

g ra ss la n d . L o w e r e x plo itatio n ra te s of

by geese, a l m o s t e xclusiv ely re fe rrin g

g r a s s la n d s and w in t e r c e re a ls by Taiga

to n o n -b r e e d in g co n d itio n s . The n u m ­

B ea n

Geese,

b e r of goose days ha 1 re p o rte d fr o m

Geese

and

G re a te r W h ite -fro n te d

th e se s tu d ie s w ere, in m o s t cases, of

canadensis w e re re p o rte d fr o m Scania,

th e s a m e m a g n itu d e as th o s e obtained

but one fie ld of w in t e r c e re als e x p e ri­

fr o m th e bree d ing a re a s in th e p re s e n t

enced 5,100 goose days ha "1 (N ils so n &

C a n ada

B ra n ta

study. T h e v a r i a t i o n in r a t e s of u t i l i ­

P e rs s o n

s a tio n

th e

g razing p re s s u r e s have been re p o rte d

p u b l is h e d i n f o r m a t i o n f r o m th e n o n ­

f o r th e s m a l l e r goose species, w ith up

b r e e d in g s t u d i e s a s w e l l as f r o m th e

to 10,000 goose days ha"' by B a rn a c le

was

g re a t

among

s tu d y a re a in S c a n ia .

1991).

Geese

C o n s id e r a b ly

h ig h e r

Geese B ra n ta leucopsis d u rin g th e p e r i­

In th e stu d y area th e e x plo itatio n of

od O c t o b e r - A p r il (Lok 1978, 1982).

pea fie ld s and c e re a l s tu b b le s by p o s t­

The n u t r it io n a l ca rry in g c a pa c ity of

bre e d in g Greylags w a s 100-350 goose

fr e s h w a t e r w e tla n d h a b ita ts fo r b re e d ­

days ha ' in th e m id - 8 0 s (N ilsso n

&

P ersson 1992). The e s tim a te d use of

ing

G re a te r

c a e ru le s c e n s

Snow

Geese

a tla n tic u s

A nser

at th e

B y lo t

th e Dutch p o rtio n of th e E m s D olla rd

Island

e s tu a ry by Greylag Geese as s p rin g and

assessed to be on average 2,800 goose

a u tu m n s ta g in g area ra n g ed 329-803

days ha"' (M assé et al. 2001 ). This value

goose days h a "1 fo r 1983-1994 (E sselin k

is m a r g in a lly h ig h e r th a n th e h ig h e s t

colony,

N unavut,

et aí. 1997). M a x im u m reco rd e d u t i l is a ­

re c o r d e d

tion of d iffe re n t fie ld types by Greylags

Scania area (2,550 goose days ha"1). In

and

P in k - f o o t e d

Geese

brachyrhynchus c o m b in e d

A nser

in S cotland

most

g r a z in g

Canada w a s

pressure

b ro a d -re a rin g

areas,

in

th e

how ever,

the geese have to sh a re th e p r im a r y

over a w in t e r w a s 1,350 goose days ha -1

p r o d u c t io n

fo r ley g ra s s and 640 goose days ha "1 fo r

rem oved

p e r m a n e n t g ra s s (N e w to n & C a m p b e ll

c o n s u m p tio n by live sto ck in th e d i f f e r ­

w ith

liv e s t o c k

by lawn

or

it

is

m o w e rs . The to ta l

1973). Recorded p eak gra zin g p re s su re

ent area s w a s beyond th e scope of th is

of P in k - fe e t in D e n m a r k w a s 950-1,200

study. In e ith e r case, th e grazin g p r e s ­

goose days h a "1 (L o renzen & Madsen

sure

1985). Grazing p re s s u re by mixed flo c k s

b r o o d - r e a r in g area exceeded th e c a lc u ­

of G re a te r W h ite - f r o n te d Geese A n s e r

la te d

a lb ifro n s and T u n d ra Bean Geese A n s e r

managed

on

th e

c a r r y in g

most

h e a v ily

c a p a c ity

g ra s s la n d

of

used a

in B rita in :

w e ll 1,900

fabalis ro ssicus in th e L o w e r Rhine area

goose days h a 1 (Owen 1977). In m o s t

re a c h e d

cases, th e c a lc u la te d e xp loitatio n rates

3,000

goose

days

h a "1 on

g ra s s la n d s , 2,600 goose days ha'' on

in th e s tu d y area w e re

w i n t e r barley and 3,500 goose days ha 1

lo w e r,

on w in t e r w h e a t (Mooij 1998). Van Im pe

Yddingen re fe rrin g to a s m a l l highly f e r ­

(1980) re p o rte d 1,030 goose days ha 1

tilis e d sho re meadow .

th e

h ig h e s t

c o n s id e ra b ly

v a lu e

at

L a ke

Field choice and breeding of Greylag Geese 21

W hen fledged, th e f a m ilie s as a rule

th e d e v e lo p m e n t of th is large m u s c le

im m e d ia te ly stop fe eding on th e bro o d -

mass

re a rin g areas, even th o u g h they u s u ally

fle d g in g

c o n tin u e to use th e b re e d ing lake fo r

S e d in g e r 1986). As food q u a lity d e te r io ­

ro ostin g . Instead, th e y s w itc h to g r a s s ­

ra te s t h r o u g h o u t th e bre e d in g season

la n ds s itu a te d b e tw e e n one and f o u r

(Spedding 1971), th e p ro te in c o n te n ts

in a s h o r t span (L e s a g e

&

of tim e

ne a r

G a u t h ie r

1997;

k ilo m e t e r s fr o m th e ro o s ts (N ilsson &

m ig h t

P e rs s o n

g o s lin g s are u n a b le to obtain en o ug h

1992,

1998).

T h e re

is one

re a c h

such

lo w

fo r th e

g o lf c o u rs e

m u s c le s (ef. Lesage & G a u th ie r 1998).

m o s t f a m il ie s

(to g e th e r

large n u m b e r s of n o n -b r e e d e r s

S eve ra l s tu d ie s

of t h e i r

th a t

exception to th is ru le however. On th e w ith

d e v e lo p m e n t

le ve ls

brea st

have s h o w n

th a t

and failed b re e d e rs th a t have re tu rn e d

g o slin g and ju v en ile s u rv iv a l d e cre a se s

a fte r

to

w ith in c re a s in g d e n s ity of goose p o p u ­

fo r

la tio n s (Cooch e t at. 2001, Loonen ef a/.

feed

m o u lt on

e ls e w h e re ),

th e

c o n tin u e

b ro o d -re a rin g

a rea

a b o u t one m o n th a ft e r fle d g in g , grazing

1997;

g o lf-c o u rs e

W illia m s ef at. 1993). S tu d ie s of th e

grasses

and

s t r ip p i n g

S e d in g e r

ef

at.

1998,

2001;

g ra s s -s e e d . The m o s t p rob a b le reason

B a rn a c le Goose (B la c k ef at. 1998) and

fo r th is d iffe re n ce is th a t th e food q u a l ­

S n o w Goose (Cooch e ta t. 1991, Reed &

ity on th e g o lf co u rse c o n tin u e s to be

P la n t e

h igher, o r at least as high as in a l t e r n a ­

d e c lin e s at h ig h e r de n sities. Moreover,

tive areas, w h ile it has b e co m e in fe rio r

c lu tc h

on th e o th e r b r o o d - r e a r in g areas. A

may

seasonal

(S ed in ge r et at. 1995, 2001). T his can

d e c lin e

in g r o w t h

ra te

of

1997)

show

size and be

th a t

body

b re e d in g

in flu e nce d

by

size

p ro b a b ility a d u lt

size

g ra s s is a c o m m o n ly o b served p a tte rn

e xp la in

fo r

d e n sity and lo w e r re p ro d u c tiv e o u tp u t

fo r a g e

p la n ts

g ra z e d

by gee se

a r e la tio n s h ip

b e tw e e n

high

(C argill & Je ffe rie s 1984), but tim in g of

in th e tw o species. However, S e d in g e r

th e d ec lin e v arie s a m o n g a re a s as w e ll

ef at. (1998, 2001 ) did not find any s i m i ­

as y ears (van d e r Veen et al. 1999). In

c o n tra s t

to

la r e ffe cts in th e B la c k B ra n t B ranta

A rc tic -b re e d in g

geese, th e Greylag s e e m s una b le to m a in ta in

a

p r o f it a b ly

sh o rt

sw a rd . A t Lake F jä llfo ta sjö n , g ra z in g 1990s,

by live s to ck th e

s in c e

fle d g in g

g ra s s lackin g

th e r a te

m id was

n ig rica n s, n o r Reed & P lante (1997) in th e G re a te r S n o w Goose. In

th e

G re yla g

Goose,

d e n s ity -

d e p e n d e n t e ffe c ts w e re fo u n d on th e n u m b e r of s m a l l young K lo s t e r v ik e n

but

not

p ro du ce d at at

Y ddin g e n .

s ig n ific a n tly lo w e r th a n at th e o th e r

F u rth e r m o re , th e average n u m b e r of

lakes. M o st of th is a d d itio n a l m o r ta lit y

fle d ge d young p e r bro od w e re lo w e r at

o c c u rre d a ro u n d fle d ging ti m e (Hakon

K lo ste rvike n tha n at Yddingen. There

Persson, pers. obs.). B re a s t m u s c le s

w e re also d iffe re n c e n s in w e ig h t of th e

s ta r t to g ro w very late, w h ic h c o n c e n ­

young and s u rv iva l ra te of th e fledged

tr a te s th e re so u rc e r e q u ir e m e n t s fo r

young be tw e en th e tw o la k es (N ilsson

22 Field choice and breedng of Greylag Geese

e t al. 1997). Lake Yddingen had s ig n if i­ c a n tly he a v ier young

th a t sho w e d

a

Nordic Greylag Geese A n se r anser. Ornis Svecica 11:19-58.

h ig h e r f i r s t - w i n t e r

s u rviva l th a n

th e

yo u n g

K lo s t e rv ik e n .

The

energy budgets of Greater Snow Geese

brood re a ring a re a s at both lakes had

Chen caerulescens atlantica staging in two habitats in spring. Ardea 77: 3-20.

high

fro m

Lake

d e n sitie s of both

breeding

and

n o n -b r e e d in g geese, m a k in g c o m p e t i­ tio n

b e tw e e n

n o n -b ree d in g

b re e d in g

b ird s

and

likely. T he

easy

Bédard, J. & Gauthier, G. 1989. Comparative

Black, J . M., Cooch, E.G., Loonen, M.J.J.E., Drent, R. & Owen, M. 1998. Body size v a ri­ ation in B a rn a c le Goose colonie s:

access to h ighly fe rtiliz e d g ra s s on the

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