Radio-Tagged Pacific Golden-Plovers: Further Insight concerning the Hawaii-Alaska Migratory Link

2004·3.2 MB·English

by  Oscar W Johnson

Wilson Bulletin, 116(2), 2004, pp. 158-162
RADIO-TAGGED PACIFIC GOLDEN-PLOVERS: FURTHER INSIGHT
CONCERNING THE HAWAII-ALASKA MIGRATORY LINK
OSCAR W. JOHNSON,' « COREY D. ADLER,^^ LEE ANNE AYRES,^
MARY ANNE BISHOP,^ JODI E. DOSTER,^^ PATRICIA M. JOHNSON,'
RONALD J. KIENHOLZ,^ AND SUSAN E. SAVAGE^
—
ABSTRACT. We radio-tagged 55 Pacific Golden-Plovers (Pluvialisfulva) in spring 2001-2003 on wintering
grounds in Hawaii. Following their northward migration (most birds deserted winter territories in late April),
we relocated 15 golden-plovers in three regions of Alaska: Copper River Delta, King Salmon, and Kotzebue.
One individual made the transpacific flight from Oahu to the Alaska Peninsula in a minimum time of 70 hr at
a minimum flight speed of56 km/hr. Our findings, together with earlierrecords, indicate a major Hawaii-Alaska
migratory connection for this species, and suggest that plovers wintering on Oahu nest throughout the known
Alaska breeding range. Post-breeding, 84% ofthe sample birds returned to Oahu and reoccupied their previous
winter territories. Received 21 November 2003, accepted 10 June 2004.
The first investigations of radio-tagged Pa- METHODS
cmiifdi-cPaGcoilfdiecn-fPllyowvaeyrswe{rPleuvciaolnidsucfutlevda)inon19t9h6e ploOvveersr otnhreOeahsupr—in2g0seeaascohnsi,n w20e01caaptnudre2d00525,
and 1999. In these studies, birds from winter-
and 15 in 2003. The birds (24 adult males, 22
ing populations on Oahu, Hawaii, were found
adult females, 3 first-year males, and 6 first-
after transoceanic spring migration at three lo- year females) were caught mostly during the
cations in Alaska (Johnson et al. 1997, third week of April with mist nets on lawn
2001a). While migrating northward, one of
areas at three wintering ground study sites:
the plovers spent time at the Copper River
National Memorial Cemetery of the Pacific,
Delta stopover and then proceeded on to
Hickam Air Force Base, and Bellows Air
breeding grounds in the Nushagak River
Force Station. These are the same sites where
drainage northwest of Lake Iliamna; others
plovers were radio-tagged in previous inves-
NweursehagdaetkecRtievder(aprreeasuamnadbloyn tnheestiYnugk)oni-nKutsh-e tigations (Johnson et al. 1997, 2001a). We
uniquely color-banded each plover and glued
kokwim Delta. Here, we present additional te-
lemetry findings that further clarify spring a 1.65 g, 60-day life span transmitter (Holohil
movements and destinations of plovers in Systems, Carp, Ontario) to feather stubs on
Alaska. We also report the post-breeding re- the lower back (see Warnock and Warnock
1993). Such attachment was temporary, as ra-
turn rates to wintering territories in Hawaii.
dios would be expected to fall offduring sum-
mertime prebasic molting on the tundra (John-
MT' D5e9p7t1,7o,fUEScAol.ogy, Montana State Univ., Bozeman. son and Connors 1996). Based on the weights
Bec-hUa.rSo.fFiNsahtiaonndalWiWlidlldilfiefeSerRveifcueg,e,AlaPs.kO.a PBeonixn.s2u7l7a./ o=f b1i7r3dsgc,lorsaensgteto=mi1g4ra8t-o2r0y7dge,panrtu=re1(8m;eaalnl
King Salmon, AK 99613, USA. captured on either 19 or 20 April, about 1
^U.S. Fish and Wildlife Service, Selawik National week pre-migration) plus comparable data
Wildlife Refuge, P.O. Box 270. Kotzebue, AK 99752, from the same sites in other years (Johnson et
USA. OWJ
^Prince William Sound Science Center, P.O. Box al. 1997, 2001a; unpubl. data), the at-
705, Cordova, AK 99574, USA. tached transmitters generally averaged less
P.O. Box 503, Gallatin Gateway, MT59703, USA. than 1% of total mass at migration. For ad-
^Current address: Alaska Coop. Fish and Wildlife ditional information on capture, marking, and
Research Unit. Univ. ofAlaska, Fairbanks, AK99775, determination of sex and age, see Johnson et
USA.
^Current address: P.O. Box 143, King Salmon, AK al. (1997, 2001a, 2001b).
99613, USA. All of the radio-tagged plovers defended
^Corresponding author; e-mail: specific winter territories on lawns at the study
owjohnson2105 aol.com sites; thus, we could monitor them easily after
158
—
Johnson et al. • RADIO-TAGGED PACIFIC GOLDEN-PLOVERS 159
FIG. 1. Detections of radio-tagged Pacific Golden-Plovers {Pliivialis fiilva) in Alaska. Numbers in circles
representthe presentstudy (2001-2003), numbers in squaresshowpreviousfindings(Johnsonetal. 1997,2()()la).
Over all years, we recorded 32 detections of 28 birds. Four individuals made long-range movements following
first detection (see text). Darker gray shading shows the approximate nesting range of P. fnlvci in Alaska.
Abbreviations: CRD (CopperRiverDelta), Anc (Anchorage), KS (King Salmon), Nu (Nushagak Riverdrainage).
Be (Bethel), Ko (Kotzebue).
release. We checked for the presence of projects involving the same aircraft. The areas
tagged birds several times a day (with a radio traversed by monitoring (lights were approx-
receiver and/or visually), and considered dis- imately as follows: Copper River Delta
appearance from a territory as an indicator of coastal Hats f—rom Cordova to Controller Bay:
migration (Johnson et al. 1997, 2001a, King Salmon Dillingham—to llnik, coastline
2001b). This plover is strongly site-faithful to to 10 km inland: Kotzebue Ki\alina to Deer-
winter territories from one season to the next ing, coastline to 30-50 km inland. Fhere were
(Johnson and Connors 1996, Johnson et al. 2-3 nights per season in the Kotzebue region.
1997, 2001a, 2001b), which enabled deter- Monitoring elTorts were more v—ariable in the
mination of return rates in the fall. other areas: C\)pper River Delta 19 Mights in
In Alaska, we monitored radio frequencies 2001, 6 in 2002, 1 in 2003: King Salmon
in the Copper River Delta, King Salmon, and 1 1 Mights in 2001, 7 in 2002, 2 in"2003. With
Kotzebue regions (Fig. 1) using lixetl-wing the exception of the ('opi^er River Delta, we
aircraft equipped with VHF receiving anten- recorded (il\S coordinates whenever a radio-
nae. Aerial surveys were conducted from late tagged plover was tletected.
April to the third week of May at the (\)pper REsuns
River Delta and King Salmon areas, and from
mid-May to mid-.Iimc at Kot/ebuc. Surveys During the 2001 2003 spring seasons, mi-
were typically coincident with other telemetry gratory departure (as iiulieated by disappear-
160 THE WILSON BULLETIN Vol. 116, No. 2, June 2004
ance of birds from their winter territories) oc- between our last contact with the bird on
eurred from 17 April to 9 May, with almost Oahu and its relocation in Alaska. Following
all departures taking plaee in late April. Col- its detection south of King Salmon, this bird
lectively, 44 of the 55 plovers (80%) departed then moved northward to breeding grounds near
from 22 to 29 April, 3 birds (5%) disappeared Kotzebue. In the Kotzebue survey area, we
before 22 April, and 8 (15%) after 29 April. found six radio-tagged plovers, including the
Much the same pattern (OWJ unpubl. data) aforementioned 70-hr individual and CRD 1.
was observed in our 1996 and 1999 studies, Eighty-four percent of the sample popula-
when 56 of 60 birds (93%) disappeared from tion (46 of 55 birds) returned to Oahu during
23 to 29 April, 1 bird (2%) before 23 April, the first fall after banding and each bird re-
and 3 birds (5%) after 29 April. Based on occupied its previous winter territory. The re-
combined records from all plovers we have turn rate did not differ significantly (y^ =
radio-tagged (65 males and 50 females in 0.33, df = 1, F = 0.56) from that of plovers
1996, 1999, and 2001-2003), earlier depar- that were banded, but not radio-tagged, at the
tures were somewhat male-biased. Over all same study sites (144 of 166, 87%; Johnson
years, 97% of males and 82% of females had et al. 2001a). Of the nine individuals that
left their territories by 29 April; the last birds failed to return, five were females and four
at our study sites each spring were typically were males. Based on all plovers we have ra-
females. There was no indication that radio- dio-tagged (Johnson et al. 1997, 2001a; plus
tagging delayed departures, as tagged and un- the present sample), there was no difference
tagged birds deserted theirterritories at similar between the sexes among birds that did not
rates, and generally the last few individuals to return (10 of65 males versus 8 of50 females;
leave were untagged. More females (10) than = 0.01, df = 1, P = 0.93).
males (5) were relocated in Alaska from 2001
DISCUSSION
to 2003, but there was no statistical difference
between the sexes (x“ = 0.13, df = P = Relocation of two radio-tagged birds at the
0.72) when relocations in previous studies Copper River Delta from late April to early
(Johnson et al. 1997, 2001a) were combined May 2001, and another individual in 1996
with the present sample. Over all years, 15 of (Johnson et al. 1997), indicates that some Pa-
65 males and 13 of 50 females radio-tagged cific Golden-Plovers migrating from Hawaii
on Oahu were relocated in Alaska (Fig. 1). use the delta region as a refueling site. Wheth-
The number ofbirds detected varied among er this is an intended landfall or a deflection
years: nine in 2001, hve in 2002, and one in caused by prevailing winds during transoce-
2003. Inter-year variation apparently resulted anic passage is uncertain. Repeated contacts
from the number of flights per season, survey with the radio-tagged plovers at the delta sug-
timing (either too early or too late), lack of gested that their stays there lasted about 1
plover-specific monitoring (i.e., coverage was week. Following this stopover, both of the
probably compromised by coincident moni- 2001 birds moved westward and each was de-
toring of frequencies from other telemetry tected again in tundra habitat where they may
projects), and weather factors that reduced the have been nesting (Fig. 1). The 1996 bird
duration and/or effectiveness of some flights. made a similar movement from the delta to
We relocated two plovers (CRD 1 and CRD the Nushagak River region, where it was de-
2) at the Copper River Delta in 2001. From tected in late May (Johnson et al. 1997).
this stopover, situated well to the east of the Detection of 12 radio-tagged plovers in the
nesting range, each—bird moved westward and King Salmon region (10 from the present
was detected again CRD 1 to the south of study; 2 previously, Johnson et al. 1997,
Kotzebue, and CRD 2 to the south of King 2001a) from Port Heiden to the mouth of the
Salmon. Assuming straight-line distances, Kvichak River (between 57° and 59° N) sug-
these flights were about 1,100 and 750 km, gests that this part of the Alaska Peninsula is
respectively. Ten plovers (including CRD 2) an important spring destination for birds win-
were found along the western edge of the tering on Oahu. Some birds stopping here are
Alaska Peninsula and west of King Salmon en route to areas much farther north (as shown
(Fig. 1). One set a record of70 hrelapsed time by one radio-tagged plover subsequently re-
.
Johnson et al. • RADIO-TAGGED PACIFIC GOLDEN-PLOVERS 161
located near Kotzebue); others may be in pas- 2003 and 13 of 60 (22%) in previous years.
sage to less distant breeding grounds, such as Our findings suggest that a substantial portion
the Nushagak River drainage (Fig. 1; Bennett of the birds wintering on Oahu breed in Alas-
1996, Johnson et al. 2001a). It is also possible ka. Whether some fraction of Oahu birds
that some of the birds detected on the Alaska breeds in eastern Siberia is unknown. Ourdata
Peninsula are nesting there. During a 15 May- also suggest that plovers wintering on Oahu
5 June 2002 shorebird survey at various sites nest throughout the known breeding range in
on the peninsula, C. Wightman (in litt. 2002) Alaska (Fig. 1). Similar linkages seem likely
“recorded Pacific Golden-Plovers performing for plovers wintering elsewhere in Hawaii, but
display flights to approximately 57 degrees 30 proof will require additional radio-tagging in
minutes latitude,” essentially the same lati- other parts of the archipelago.
tude where we received signals from several ACKNOWLEDGMENTS
of our radio-tagged birds. The timing of
Wightman’s observations strongly suggests The project was funded by the U.S. Fish and Wild-
that they represented breeding birds, but as yet life Service, Hawaii Audubon Society, and private do-
no intensive nest searches have been con- nors participating in Kolea Watch. The latter program
(administered by the Hawaii Nature Center in Hono-
ducted. If nesting is confirmed at that latitude, lulu) provides educational opportunities for people of
it would extend the breeding range at least all ages interested in Pacihe Golden-Plovers. Support
250 km farther south than currently recog- for MAB was through a grant from the Prince William
nized (Fig. 1; also see Johnson et al. 2001a). Sound Oil Spill Recovery Institute. Aircraft and radio
The minimum flight time of 70 hr from equipment were made available by the U.S. Fish and
Oahu to near Port Heiden on the Alaska Pen- Wildlife Service. G. Castagnetti and various officers
and officials in the U.S. Air Force kindly provided
insula is the shortest interval thus far recorded access to plover wintering grounds on Oahu. Many
(previously 90 hr, see Johnson et al. 1997) for people helped us in Hawaii with capturing and radio-
the transpacific passage. Assuming a great cir- tagging plovers, monitoring their migratory departure,
cle route of approximately 3,900 km, this and assisting with other elements of the project; we
bird’s minimum flight speed was 56 km/hr. are especially grateful to A. Bell, G. Bodner, S. Gais-
Given the high-speed flight characteristic of ford, K. Gaisford, K. Gingrich, A. Jeffers-Fabro, A.
the species (Paulson 1993, Johnson and Con- Kienholz, J. Lee, E. Penn, M. Roney, L. Shapin, and
nors 1996), the actual flight time was probably rS.ecoSroduitnhgwotrhtehf.allP.reBtruurnneorfmaandrkeA.d bBirrudsneornaOsashiust.edThien
less and the speed greater than we recorded. following individuals were invaluable to the aerial sur-
Measurements of flight-time and speed are vey efforts in Alaska: K. Becker, J. Bertrand, D. Cox.
complicated by a number of difficult-to-re- N. Gregory, A. Leppold, B. Meixell. T. Moran. T
solve variables, including time spent in pre- O’Hara (decea.sed), M. Prehoda, and S. Ranney. We
departure staging, routes followed, and the in- thank B. Andres, J. Bart, and N. Warnock for their
helpful reviews of the manuscript.
terval between arrival and detection in Alaska.
The relatively high rates of fall returns con- LITERATURE CITED
firmed earlier conclusions (Johnson el al. Bi:nni:it. A. .1. 199b. Pacific and American Golden-
1997, 2001a) that radio-tagging caused no ap- Plovers breeding in southwestern Alaska. North-
parent harm to the birds. While this is reas- western Naturalist 77:49-51.
suring, it remains uncertain whether transmit- .loHNSON, O. W.. A. .1. Bi;nni it. L. Aiswokhi. 111. 1,
ters interfere in any way with the reproductive A. Bt;NNi;iT, P. M. .Iohnson. .1. R. Mokcaki, \m)
process. Both .sexes returned at equal rates and R. J. Kii;nu()I /.. 2001a. Radio-tagged Pacific
Golden-Plovers: the Hawaii-Alaska link, spring
this further substantiated past findings (in part
destinations. ;uul breeding season sur\i\al. .lour-
from birds not radio-tagged) of no sex-related iKil of Pield Ornithology 12:5M .*^4b.
bias in mortality during the migration or .loiiNsoN, O. W.. P I.. liKi \i K, .1. .1. Rohm \. I’. M.
breeding periods (Johnson et al. 1993, 2001a, .Iohnson. and A. F. Bki ni k. 2001b. Long-term
200lb; OWJ unpubl. data). study of apiiarent sui\i\al in Paeilie Golden Plo-
Our aerial surveys in Alaska covered a rel- vers ;it a wintering grouiul on Oahu. Hawaiian Is
atively small fraction (probably <\(V/f of the laiuls. Auk I IS;.H2 I
area in which Pacific Golden-Plovers) cither JohnsGoonl.deOn.PWU.nei\nd(UPn.vGi.oUCsondonmoirnsi.id)I.99Pba.ci.fAimceGroilcadn
nest or likely stop to refuel. Nonetheless, we en Plo\ei (/Jnvialis fnivo). The Muds of North
relocated 15 of 55 (217r) frt)m 2001 through .America, nos. 201 202.
162 THE WILSON BULLETIN • Vol. 116, No. 2, June 2004
Johnson, O. W., P. G. Connors, P. L. Bruner, and J. Plovers from Hawaii to Alaska, and their subse-
L. Maron. 1993. Breeding ground fidelity and quent survival. Auk 1 14:521-524.
mate retention in the Paeitie Golden-Plover. Wil- Paulson, D. R. 1993. Shorebirds ofthe Paeitie North-
son Bulletin 105:60-67. west. University ofWashington Press, Seattle.
Johnson, O. W., N. Warnock, M. A. Bishop, A. J. Warnock, N. and S. Warnock. 1993. Attachment of
Bennett, P. M. Johnson, and R. J. Kienholz. radio-transmitters to sandpipers: reviewand meth-
1997. Migration by radio-tagged Paeitie Golden- ods. Wader Study Group Bulletin 70:28-30.