• Declines in Aleutian and Arctic tern numbers were highest at large colonies on the southeastern end of Kodiak Island.

• Intra-and inter-annual variability in counts was high most likely as a result of high nest failure, variable rates of re-nesting, and colony abandonment.

• Egg survival to hatch was low as a result of depredation and abandonment.

Status and Nest Survival of Aleutian and Arctic Terns breeding in the Kodiak Archipelago, Alaska, 2016-2018

IntroductionAleutian terns (Onychoprion aleuticus) are colonial nesting seabirds that breed in coastal Alaska and the Russian far east, often in association with Arctic terns (Sterna paradisaea). Recent trend analysis of numbers of Aleutian terns at colonies in Alaska indicates that this poorly known seabird has declined by 80% over the past three decades. The much more abundant and widely distributed Arctic tern also appears to have declined by more than 90% regionally in coastal locations in the Gulf of Alaska. However, there is a high degree of uncertainty in breeding population status of both species due to their scattered and remote nesting locations, and variable site fidelity and colony attendance patterns.

Goal 1: Count terns at known colonies, search for new nesting locations, and compare results to previous surveys

Conclusions

AcknowledgementsWe sincerely thank the seasonal avian monitoring interns who volunteered on surveys including Amee Van Tatenhove, SJ Kwiatowski, Eva Kwiatek, Kristy Lapenta, Emily Johnson, and KNWR biological technicians Tim Knudson and Katie Stoner. We thank the staff of the Kodiak NWR for help with logistics, in particular Jeff Lewis, Captain of the Refuge research boat the Ursa Major II. We thank Rich MacIntosh for help with surveys and generously sharing many years of survey data.

Jill E. Tengeres1, Robin M. Corcoran2, and Donald E. Lyons1,3

1Department of Fisheries and Wildlife, Oregon State University; 2U.S. Fish and Wildlife Service, Kodiak National Wildlife Refuge; 3National Audubon Society Seabird Restoration Program

• During the 2016-2018 breeding seasons we surveyed for terns at the 53 known breeding sites and located 7 new sites. • Aleutian terns were observed at 16 colonies and colony size varied from 1 to 212 individuals. • Arctic terns were observed at 47 colonies and colony size varied from 1 to 150 individuals.• Declines between decades were most evident at previously large colonies on the southeastern end of Kodiak Island.

Intra-and Inter-annual Variability• Coefficient of Variation (CV) on counts varied from 0.33 – 2.66 for

Aleutian terns (ALTE) and 0.44 to 1.76 for Arctic terns (ARTE).

Goal 2: Document variability in colony counts to inform state-wide monitoring plans

Coefficient of Variation (June 1 – August 1)

Aleutian Tern Arctic Tern

Site 2016 2017 2018 2016 2017 2018

Middle Bay

0.41 (n = 7 counts)

0.33(n = 9 counts)

0.75(n = 9 counts)

1.37(n=4 counts)

1.76(n=10 counts)

1.23(n= 9 counts)

KalsinBay

1.31 (n = 15 counts)

2.66(n = 12 counts)

0.95 (n = 11 counts)

0.44(n=5 counts)

1.41(n=11 counts)

0.46(n= 11 counts)

• Counts from early June to mid-July capture peak nesting.

0

1000

2000

3000

4000

5000

1970's 1980-90's 2000's 2010's

Tota

l # o

f In

div

idu

als

Decade

Aleutian Terns - East Kodiak

0

20

40

60

80

Tota

l # o

f In

div

idu

als

Aleutian Terns - West Kodiak/Afognak

0

100

200

300

400

500

600

700

Tota

l # o

f In

div

idu

als

Aleutian Terns - Kodiak Road System

0

2000

4000

6000

8000

10000

1970's 1980-90's 2000's 2010's

Tota

l # o

f In

div

idu

als

Decade

Arctic Terns - East Kodiak

0

200

400

600

800

Tota

l # o

f In

div

idu

als

Arctic Terns - Kodiak Road System

0

200

400

600

800

1000

Tota

l # o

f In

div

idu

als

Arctic Terns - West Kodiak/Afognak

West Kodiak/Afognak

Road System

East Kodiak

Road SystemWest Kodiak/Afognak

East Kodiak

0

20

40

60

80

100

120

25-Apr 14-Jun 3-Aug 22-Sep

Nu

mb

er

of

Ind

ivid

ua

ls

Date

Middle Bay ALTE_2018ALTE_2017ALTE_2016

0

10

20

30

40

50

60

70

25-Apr 14-Jun 3-Aug 22-Sep

Nu

mb

er

of

Ind

ivid

ua

ls

Date

Kalsin Bay ALTE_2018ALTE_2017ALTE_2016

0

10

20

30

40

50

60

25-Apr 14-Jun 3-Aug 22-Sep

Nu

mb

er

of

Ind

ivid

ua

ls

Date

Middle Bay ARTE_2018ARTE_2017ARTE_2016

0

20

40

60

80

100

120

25-Apr 14-Jun 3-Aug 22-Sep

Nu

mb

er

of

Ind

ivid

ua

ls

Date

Kalsin Bay ARTE_2018ARTE_2017ARTE_2016

Goal 3: Determine Nest Survival & Causes of Failure• We used Reconyx digital cameras to monitor nest survival through hatch.• Analysis is on-going but daily nest survival was estimated at 0.86. • Predators – mainly red fox; but also mew and glaucous-winged gull,

northwestern crow, black-billed magpie, brown bear, short-tailed weasel.• Nest abandonment was common due to disturbance and flooding.

Aleutian tern nest