Thursday, January 26, 2012

Baby on Board


A few weeks ago, Chan Chich Lodge guest snapped this unusual photograph of a Short-tailed fruit bat (Carollia sp.).  Liz took this great photo in the Upper Plaza, right next to the Lodge.  Short-tailed fruit bats are very common throughout tropical Central and South America.  They play a very important role, consuming fruits and dispersing copious numbers of seeds in their droppings.  Many of the seeds are important colonizers helping the forest to regenerate in denuded areas.

What makes Liz's photo so charming and unique is the baby on board.  Can you imagine the energy and strength it takes to fly carrying a baby one third your size?

Thursday, January 19, 2012

White Heron ... or Egret?

This mystery bird has been hanging around Gallon Jug for the past several weeks.  More specifically, along the Rio Bravo in Sylvester Village.  My neighbor Alan finally snapped photos of it, which took the ongoing local debate to a higher level.  At first glance, you'd assume it was a Great Egret (Casmerodius albus).  Common enough and readily seen in Gallon Jug during the winter months.  Something about the bill doesn't seem quite right though ... and it is using a slightly different habitat than we are accustomed to seeing for Great Egrets.  This bird seems to prefer shady areas along the river rather than the more open areas where we Great Egrets are more readily seen.

That habitat preference seems a bit more Great Blue Heron-ish (Ardea herodias) and it sort of has the Great Blue's form.  In fact, there is a rare white morph (=form) of the Great Blue Heron called Würdemann's Heron found only in the Caribbean .  And it's apparently not been recorded inland.  So is this Würdemann's Heron?  Our references were inconclusive.We consulted an upcoming ornithologist here in Belize, Roni Martinez, to get his opinion.  This is what he had to say:
"This bird is almost certainly a white morph Great Blue Heron ... note the white plume originating on the back of the crown and the gray, not black, legs. Great Egrets have black legs and do not have neck/crown plumes. Also, the bill is too thick for Great Egret."
 The Audubon Society Master Birding Guide  shows yellow legs and yellow bill as a field marks for the "Great White Heron" (aka Würdemann's Heron).  The photographed bird clearly has dark legs. The same reference says "yellow bill, black legs and feet" on the immature Great Egret.  That said, I do agree that the bill appears heavier.

  Roni replied:
"The legs on the Rio Bravo bird are definitely darker than normal but they are not black. The bill is right on for Great White, and the single head plume by itself eliminates Great Egret. The Sibley Guide has an illustration of a Great White Heron that approaches the bird in the photograph. Also check out the bill shape and color in the photo at http://www.oceanwanderers.com/NYGWHeron.html  

"I am no expert by any means on Great White Heron, so you should get a second opinion from someone with more experience with the species. Keep in mind that soft part colors (legs, bill, eyes) on Great White Heron are likely to be more variable than in a true species like Great Egret. Various intermediate stage between the Great White morph and the Great Blue morph are frequent (e.g., Wurdemann's Heron), and the Great Blue morph does have dark legs."
 So what do you think?  Opinions?  Guesses anyone?  Alan is going to try to get another photograph of it ... thanks Alan!


Wednesday, January 11, 2012

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 22nd 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 5th 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

Friday, January 6, 2012

Rainy Day in the Neighborhood

If these vultures look a little dejected, it's because they are soaking wet and have been for the past few days.  Seems we had near record rain ... and over the Christmas Bird Count too.  Still, we managed to muster a few teams of hardy souls, braved the elements and conducted our count on 31 December.  Those of you facing snow and ice on your Christmas Counts likely do not feel too sorry for us.  Even so, torrential downpours beginning late morning and lasting throughout the afternoon put a "damper" on bird activity.  We are still tabulating "count week" birds and I'll post the results next week. Stay tuned!