Song and the city: Avian flexibility in a noisy world
Transcript of Song and the city: Avian flexibility in a noisy world
Hans SlabbekoornInstitute of Biology, Leiden University (IBL)
The Netherlands
Song and the city: Avian flexibility in a noisy world
Urbanization leads to homogenization of avian fauna
A BC C D
EFG FGC CB D
EA
Clergeau et al./McKinney et al. Biol. Cons. 2006
Urban survivors that remain and seem to thrive
Stockwell et al. 2003, after Gomulkiewicz & Holt Evolution 1999
Ecology beats Evolution
Evolution beats Ecology
High extinctionrisk
Potential importance of behavioural plasticity
Is traffic noise a factor?Which bird species do well and why?
(Foppen & Deuzeman: DLN 2007)
Road closed
Anthropogenic noise negativelyaffects reproductive success
• Male ovenbirds of noisy territorieshave 17 % lower pairing success(Habib et al. J. Appl. Ecol. 2007)
• Pairs of great tits in noisy territorieshave lower clutch size and lowernumber of fledgelings(Halfwerk et al. J. Appl. Ecol. 2011)
8.0
6.0
4.0
2.0
0
D
FO
RE
ST
FE
Fre
que
ncy
(kH
z)
Time (seconds)
0.25 0.5 0.25 0.5 0.25 0.5
UR
BA
NF
req
uen
cy (
kHz)
8.0
6.0
4.0
2.0
0
Signal-to-Noise Ratio lowerhigher
8.0
6.0
4.0
2.0
0
FO
RE
ST
Fre
que
ncy
(kH
z)
Time (seconds)
0.25 0.5 0.25 0.5 0.25 0.5
UR
BA
NF
req
uen
cy (
kHz)
8.0
6.0
4.0
2.0
0
Signal-to-Noise Ratio lowerhigher
Urban noise affects low frequencies most
(Nemeth & Brumm, Am.Nat. 2010)
Singing high is beneficial to urban signal range
Cuckoo Nuthatch Wren Flycatcher Tanager Thrush Ovenbird Flycatcher
(Goodwin & Shriver: Cons. Bio. 2011)
Bird occupancy in quiet (white bars) and noisy(gray bars) forest plots in Virginia (n=2 x15)
(Francis et al. Curr. Biol. 2009)
Rattlesnake Canyon, San Juan Basin in New Mexico (which has over 20,000 active oil and gas wells):
All identical with or without noisy compressor (24 hours a day, 365 days a year)
Hummer Bushtit Sparrow Finch Grosbeak Tanager Dove
(Francis et al.: PLoS ONE 2011)
Nesting
N=30
(Hu & Cardoso: Behav. Ecol. 2009)
2/3
Comparison of phylogenetically matched species groups of urban and non-urban habitat
1/3
A New/Urban/Noisy
Environment
Son
g fr
eque
ncy
Impact of behavioural plasticity?
3100
3200
3300
3400
3500
3600
3700
URBAN FOREST
Fre
que
ncy
(kH
z)
Paired t-test: n=10, t=7.86, p < 0.001
Forest
Urban
Ten city-forest pairs across Europe are consistently different in frequency use
(Slabbekoorn & den Boer-Visser: Current Biology 2006)
Intra-specific variation
Time (seconds)
Fre
quen
cy (
kHz)
10.0
8.0
6.0
4.0
2.0
00.5 1.0 1.5
Leiden - quiet territory
Time (seconds)
Fre
quen
cy (
kHz)
10.0
8.0
6.0
4.0
2.0
00.5 1.0 1.5
Leiden - noisy territory
2750
3000
3250
3500
3750
4000
40 45 50 55 60 65
(Slabbekoorn & Peet: Nature 2003)
Min
imu
m F
req
uen
cy (
Hz)
Pearson’s r = 0.377, n = 32 & p < 0.05
Noise level in dB(A)
Loud low-frequency noise correlatedto singing high in Leiden great tits
Intra-population variation
Replication of noise-dependent frequency use
Longer bouts for song types that do well under current noise conditions
(Halfwerk & Slabbekoorn, Animal Behaviour 2009)
EXPERIMENTAL EVIDENCE
(Parris & Schneider: Ecol Soc. 2009)
Not all species exhibit noise-dependent frequency use
Grey Shrike-Thrush Grey Fantail
(Ríos-Chelén et al. J. Evol. Biol. 2012)
Not all species exhibit noise-dependent frequency use
Stockwell et al. 2003, after Gomulkiewicz & Holt Evolution 1999
Ecology beats Evolution
Evolution beats Ecology
High extinction risk
But does it help? And what did they use it for anyway?
We still lack data on reproductive benefitsfor urban breeders that shift upward relative
to those that do not
Furthermore, there may be reproductive costsfor urban breeders that shift upward relative to
those that do not
Great tits sing their lower song types more often when eggs are being fertilized
(Halfwerk et al. PNAS 2011)
??
No EPC EPC
Great tit females of males that sing lower song types more often exhibit higher fidelity
(Halfwerk et al. PNAS 2011)
So, great tits may reduce masking but compromise mate attraction function
(Dabelsteen & Pedersen, Anim. Behav. 1990; Ripmeester et al. Ethology 2007)
More twitters can signal aggression
N=24 N = 27
Blackbirds sing longer twitters in cities
(Ripmeester et al. BES 2010)
Correlation between twitter use and density
= forest
= city
Habitat Territorial density
URBAN ANGER
So, blackbirds may reduce masking but may compromise motivational signalling
Summary• Urban noise can affect reproductive success
• Noise impact is frequency-dependent
• Urban birds sing higher all over the world
Ecology beats Evolution
Evolution beats Ecology
High extinction risk
• Song plasticity could save city species
• But, we need more evidence for benefits
• And, there may be costs like “Urban Anger”
Je vous remerci pour votre attention!
Margriet PeetArdie den Boer-Visser
Erwin RipmeesterWouter Halfwerk
Peter SnelderwaardHerman Berkhoudt
Carel ten Cate