Figure 1.
Migration routes, stopover locations, breeding, and wintering areas for bar-headed geese marked at Qinghai Lake.
Migration routes are shown for the 15 individuals (each in unique color) that completed at least one fall migration. White polygons represent stopover areas. Individual 82081 (red path, full path in inset) wintered in India. Individuals 74898 (orange) and 82084 (yellow) are highlighted in Figure 3.
Table 1.
Breeding, post-breeding, spring and fall stopover, and wintering areas used by bar-headed geese captured at Qinghai Lake, 2007–2008.
Table 2.
Migration chronology and movement rates of bar-headed geese marked at Qinghai Lake during fall and spring migration, 2007–2008.
Figure 2.
Brownian bridge utilization distributions in relation to poultry density and HPAI H5N1 outbreaks.
Brownian bridge utilization distributions (A) describe fall (yellow; 27 Sep–9 Dec) and spring (orange; 6 Mar–22 May) goose migrations. Fixed kernel home ranges depict (B) population level breeding and post-breeding areas (C) and wintering areas, with only locations near outbreaks shown. Brown shading indicates poultry densities. H5N1 outbreak events in wild birds (white) and poultry (black) are indicated for 2003–2009. Two shading levels indicate isopleths containing 95% (red) and 99% (yellow-orange) of total locations.
Figure 3.
Concurrent use of natural wetlands and agricultural fields by wintering bar-headed geese near Lhasa.
(A) Winter movements for goose 74898 (3 November 2007–2 April 2008; 1205 locations) in relation to a confirmed HPAI H5N1 outbreak in chickens on 21 January, 2008 (black circle). (B) Winter movements (9 November 2008–5 April 2009; 961 locations) for goose 82084 in relation to a captive bar-headed goose farm (red circle).
Figure 4.
Bar-headed goose farming in Tibet.
(A) Captive bar-headed geese in Gonggar County, Tibet as shown in a December 2007 China Tibet Information Center article (Wu 2007). (B) Wild bar-headed geese (foreground) shown in close proximity to a captive bar-headed goose farm (blue building in background) in a January 2007 photo from an anonymous source. Approximately 250 bar-headed geese were counted in outdoor net pens attached to the building (out of view in photo B). Approximate location of this farm is shown in a red circle (Fig. 3b).
Table 3.
Percent habitat type, poultry density, and human population densities at 43,841 satellite telemetry locations in China for 29 bar-headed geese marked at Qinghai Lake, 2007–2008.
Figure 5.
Classification and regression tree describing poultry (A) and wild bird (B) outbreaks on the Qinghai-Tibet Plateau.
Numbers of random points (numerator), outbreak locations (denominator), and percentage of total sample are reported at each terminal node.
Table 4.
Akaike Information Criterion (AIC) best-fit model results for ten a priori models of domestic poultry and wild bird H5N1 outbreaks during 2003–2009 (n = 7 domestic, n = 9 wild) compared with random points drawn from minimum convex polygons per season (n = 70 domestic, n = 90 wild) on the Qinghai-Tibet Plateau.
Figure 6.
Comparison by season of wild and domestic outbreaks on the Qinghai-Tibet Plateau.
(A) Observed versus expected values differed for both poultry and wild bird outbreaks when tested separately (Fisher Exact Test, poultry P = 0.079, wild P = 0.017). (B) Temporal distribution of wild bird outbreaks differed from domestic bird outbreaks (Fishers Exact Test, P = 0.008). Expected numbers were calculated under the assumption that outbreaks are proportional to the number of days within the seasonal period (Winter = 87 d, Spring Migration = 78 d, Breeding = 126 d, and Fall Migration = 74 d).
Figure 7.
Phylogenetic relationships of HPAI H5N1inferred by neighbor-joining analysis based on 1550 bp fragment of the HA gene.
Viruses isolated from the bar-headed goose are highlighted (blue) and the monophyletic grouping of isolates from Tibet and Qinghai are indicated by a symbol (♦).
Table 5.
Top-ranked Akaike Information Criterion (AIC) models with parameter values for domestic poultry and wild bird H5N1 outbreaks on the Qinghai-Tibet Plateau.