INSTREAM BACTERIA CONCENTRATIONS

AND THEINFLUENCE OF BIRD COLONIES AT BRIDGES

DAVID PENDERGRASS

Rese

arch

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Birds poop.

Bird poop can be a major contributor to high instream E. coli concentrations.

Instream E. coli samples are often collected near bridges.

Some birds, such as cliff swallows, roost at bridges in large numbers.

Landowners in some bacteria TMDL watersheds pin blame on bird colonies at water sampling sites.

Rese

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Do birds roosting at bridge crossings significantly increase instream bacteria concentrations in the

vicinity of bridges?H0 = No significant increase in E. coli concentrations between

upstream and downstream samples

STUDY DESIGN

Stud

y De

sign

Stud

y De

sign

1 x 1 Meter Frames

Bacteria Sampling Locations

Upstream DownstreamBridge

Br

idg

e

SP, 14 June 2013

Assess Defecation Densities

Assess Instream Bacteria Concentrations

Stud

y De

sign

2 Treatment Bridges (16404 & 21186…swallows)

1 Spatial Control (20018…no swallows)

1 Temporal Control (16404… prior to swallow arrival)

1 x 1 Meter Frames

Bacteria Sampling Locations

Upstream DownstreamBridge

Br

idg

eSP, 14 June 2013

Stud

y De

sign

(5 Up + 5 Bridge + 5 Down) * 3 Events = 45 Samples

1 x 1 Meter Frames

Bacteria Sampling Locations

Upstream DownstreamBridge

Br

idg

eSP, 14 June 2013

45 Samples * 8 Visits = 360 Samples360 Samples * 2 Treatment Bridges = 720 Samples

720 Treatment Samples + 315 Control Samples = 1,035

NATURAL HISTORY

OF CLIFF SWALLOWS

Orni

thol

ogy

Cliff Swallow (Petrochelidon pyrrhonota)

In Texas: Arrive early March, depart mid-June

0

2

4

6

8

10

12

14

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Aver

age

Repo

rted

Cou

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P. p

yrrh

onot

a

Texas

Lampasas County

2003-2012

Data: www.ebird.org

Orni

thol

ogy

The Three Phases of Nesting

Cliff Swallow (Petrochelidon pyrrhonota)

Feeding/Nest Building

Incubation Nestling(Early)

Nestling(Late)

Fecal Deposition Frequency

Sortie Duration

Sortie Frequency

RESULTS

Resu

lts

Densely Populated Treatment Bridge

0

100

200

300

400

500

600

0 1 2 3 4 5 6 7 8 9

E. co

li (C

FU/1

00 m

l)

Date

Upstream

Bridge

Downstream

Geomeans

Station 16404

Geomean Criterion: 126

Apr 19 Apr 30 May 22 May 23 Apr 08 Apr 23 May 06 May 30-------------------- 2012 -------------------- -------------------- 2013 --------------------

Resu

lts

Moderately Populated Treatment Bridge

0

100

200

300

400

500

600

700

800

0 1 2 3 4 5 6 7 8 9

E. co

li (C

FU/1

00 m

l)

Date

Upstream

Bridge

Downstream

Geomeans

Station 21186

Geomean Criterion: 126

Values of 860 and 1000 at Bridge not shown

Apr 26 May 01 May 24 May 29 Apr 09 Apr 22 May 07 May 31-------------------- 2012 -------------------- -------------------- 2013 --------------------

Resu

lts

Control Bridges

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8

E. co

li (C

FU/1

00 m

l)

DateUpstream Bridge Downstream Geomeans

Apr 27 May 03 May 30 Jun 25 Jan 24 Feb 06 Feb 27------------------------- 2012 ------------------------- ---------------- 2013 ---------------

Geomean Criterion: 126

Bridge values for Survey 3 not shown. Mulitple high outliers likely caused by fish foraging in sediment.

Temporal Control - Station 16404Spatial Control - Station 20018

DISCUSSION

Disc

ussi

on

Do birds roosting at bridge crossings significantly increase instream bacteria concentrations in the

vicinity of bridges?

Yes…Sometimes…It Depends…

Disc

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on

Yes…Sometimes…It Depends…

At the densely birded bridge……….When swallows were present…

Differences were always significant between upstream and downstream samples….....

Disc

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on

Differences were less pronounced…

Differences were significant only during peak bird activity…

Meanwhile at the moderately birded bridge...

0

100

200

300

400

500

600

700

800

0 1 2 3 4 5 6 7 8 9

E. co

li (C

FU/1

00 m

l)

Date

Upstream

Bridge

Downstream

Geomeans

Station 21186

Geomean Criterion: 126

Values of 860 and 1000 at Bridge not shown

Apr 26 May 01 May 24 May 29 Apr 09 Apr 22 May 07 May 31-------------------- 2012 -------------------- -------------------- 2013 --------------------

Disc

ussi

on

No differences at nestless SPATIAL control bridge…

Significant differences at TEMPORAL control likely due to small perennial house sparrow colonies…

Furthermore, at the control bridges...

0

50

100

150

200

250

0 1 2 3 4 5 6 7 8

E. co

li (C

FU/1

00 m

l)

DateUpstream Bridge Downstream Geomeans

Apr 27 May 03 May 30 Jun 25 Jan 24 Feb 06 Feb 27------------------------- 2012 ------------------------- ---------------- 2013 ---------------

Geomean Criterion: 126

Bridge values for Survey 3 not shown. Mulitple high outliers likely caused by fish foraging in sediment.

Temporal Control - Station 16404Spatial Control - Station 20018

Feeding/Nest Building

Incubation Nestling(Early)

Nestling(Late)

Fecal Deposition Frequency

Sortie Duration

Sortie Frequency

Disc

ussi

on

E. Coli concentrations generally increased with bird activity at the nests

And the natural history…

Disc

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on

More birds = more instream E. coli

Conclusion?

Disc

ussi

onImplications for

Water Quality Technicians

Assess presence of birds (and bats?).

Sample at a BPJ distance from the upstream bridge face.

Be mindful of migratory patterns (avoid nesting periods?).

Landowners in TMDL watersheds can—but probably shouldn’t—pin high E. coli concentrations on migratory swallow colonies.

ACKNOWLEDGEMENTS

FUNDING: TEXAS STATE SOIL AND WATER CONSERVATION BOARD

NABIN BASNET, CHRISTIE GOFFINET, GEORGIANA HUDSON, JOSEPH

JACKSON, UJWAL PANDEY, MATT BROWN, AND STEPHANIE PAINTER

JESUS CHRIST

QUESTIONS

Appe

ndix

0

5

10

15

20

25

-40 -20 0 20 40

Feca

l Cou

nt

Distance From Bridge Face (m)

Downstream Upstream

16404 Median Counts

0

2

4

6

8

10

-40 -20 0 20 40

Feca

l Cou

nt

Distance From Bridge Face (m)

Downstream Upstream

21186 Median Counts

Appe

ndix

0

100

200

300

400

500

600

700

800

900

0 1 2 3 4 5 6 7 8 9 10Es

timat

ed A

ctiv

e N

ests

Total Active Nests

Nests Over Water

19 Apr 30 Apr 29 May 23 Jan 08 Apr 23 Apr 08 May 31 May

ControlSample

Date

16404

2012 2013

0

200

400

600

800

1000

1200

1400

1600

1800

0 1 2 3 4 5 6 7

Estim

ated

Act

ive

Nes

ts

Total Active Nests

Nests Over Water

27 Apr 29 May 08 Apr 22 Apr 08 May 31 May

2012 2013

21186