Summary of the 2011 Gallon Jug CBC

The 2011 Gallon Jug Christmas Bird Count was held, in conjunction with the National Audubon Society, on December 31, 2011.  This marked the 22^nd year of the Gallon Jug Estate Christmas Bird Count (GJE CBC) since it began in 1990.  Over the years there have been ups and downs in species, individual birds counted as well as in the number of participants.  Along with the variation in number of observers, there has been a range of good, bad and mixed weather conditions that influenced bird activity and detectability.

Species numbers have ranged from a low of 171 to 238 (Figure 1), averaging 203. Individuals  counted have previously ranged from 1718 to 4772 (Figure 2), averaging 2,849.  This was one of the years when intermittent heavy rain impacted bird detectability and bird activity as well as “observer” activity.  All participants experienced rain that seemed to begin just when we thought it was safe to step out of the vehicle again.

Given the slow start of the count day and the many hours of light to heavy rain, we were pleased that the 183 species recorded this year was not the lowest on record (2006 and 2007 were tied at a low of 171). However, the number of individuals counted was at an all time low with 1,646.  An additional 35 species were recorded for the Count Week, but not seen on the count day.

Figure 1.  Summary of unadjusted species recorded for each year of the GJE CBC.

Figure 2.  Summary of unadjusted individuals recorded for each year of the GJE CBC.

This year’s Top 20 are listed in Table 1 and can be compared with 2010.  During the 2010 CBC there were scant frugivores (= "fruit eaters") as a result of the impact of Hurricane Richard (October 24, 2010).  As the forest regenerates, the birds are returning and many of the frugivores that had evidently moved elsewhere in 2010, made it back into the Top 20 list for 2011.

The top species this year as in 2010, was the Ocellated Turkey. While the individual numbers recorded this year were somewhat lower, many were no doubt huddled out of sight under vegetation trying to stay dry.  This was not the case for many of the observers who were soaked to the skin.

Notably low this year with only 10 counted, was the Gray Catbird, ranked 5^th in 2010 with 94 individuals. Last year the White-whiskered Puffbird was notable with a record 32 individuals recorded.  The average number of individuals of this species per count for the previous 20 years was only 9. This year we had none.  However, 2 White-necked Puffbirds were recorded.

Table 1. The 2010-2011 Top 20.  Comparison of species with the highest individual numbers.

2011
Species	Number
Ocellated Turkey	195
Olive-throated Parakeet	119
Montezuma Oropendola	116
White-collared Seedeater	63
Brown Jay	56
Red-lored Parrot	46
Tropical Kingbird	37
Cattle Egret	36
Social Flycatcher	35
Turkey Vulture	33
Roadside Hawk	30
Keel-billed Toucan	29
Rufous-tailed Hummingbird	26
Yellow-throated Euphonia	26
Pale-billed Woodpecker	24
Plain Chachalaca	21
White-breasted Wood-Wren	21
Black-headed Trogon	20
Melodious Blackbird	20
2010
Species	Number
Ocellated Turkey	273
Cattle Egret	219
White-collared Seedeater	114
Melodious Blackbird	102
Gray Catbird	94
Turkey Vulture	87
Killdeer	86
Tropical Kingbird	83
Montezuma Oropendola	58
Wood Thrush	56
Clay-colored Thrush	54
Brown Jay	52
Black Vulture	51
Olive-throated Parakeet	48
Mangrove Swallow	46
Vaux's Swift	44
Great-tailed Grackle	42
Ruddy Ground-dove	40
Blue-black Grassquit	39

We had a total of six parties (aka “teams” or groups counting birds) with a combined time of 34 observation hours. Party results ranged from a minimum of 20 to a high of 72 species and individuals ranged from 38 to 624. Last year the number of parties and hours counted were significantly higher.

In order to compare the CBC results over time, the data is standardized by the number of party hours for each species. This is how results are posted on the National Audubon Society's CBC  web site for each year’s results. Party hours for the GJE CBC have ranged from 22.75 to 77.25 with an average of 52 per count year. By using the data standardized per 50 hours, even  with reduced hours of counting due to the rain, this year’s count of individuals, while down a bit, was actually not bad.

 

Figure 3. 2011 GJE CBC summary based on standardized number of individuals.

Based on the effort all participants put forth and standardizing the data we actually had an increase in species per party hour over last year (Figure 4).  So while there were fewer of us for a shorter time, we counted more species than the teams did last year under considerably more favorable weather conditions.

 Figure 4. 2011 GJE CBC GJE CBC summary based on standardized number of species.

As always we thank all participants, including Chan Chich Lodge guests and guides, and our Corozal contingent who traveled to be here on Count Day.  One their way to Gallon Jug, they stopped at the rice fields near Blue Creek to see the Gadwalls and Redheaded ducks, rare species for Belize.  They reported that Gadwalls were still around but the Redheads had apparently moved on.

Thanks also to Chan Chich Lodge for their continued sponsorship of the GJE CBC. We wish to especially acknowledge Victor Emanuel Nature Tours as they have contributed to all of the GJE CBCs since the beginning.  Our special thanks go to VENT leaders Brian Gibbons and Bob Sunderstrom who provided the VENT trip report that contributed to the Count Week birds, as well as their efforts during the day of the count.

Submitted by:

Bruce W. Miller PhD.

Carolyn M. Miller MSc.

Gallon Jug, Belize

January 10, 2012