Food Habits of Geese in Northern India

Regional, yearly and seasonal differences are apparent in the food habits of geese in northern India. For barheadedgeese (Anserindicus), a wild wetland grass, Paspalum distichum, isthe most important foodin the Keoladeo National Park. Elsewhere in the region, Cynodon dac-tylon, another grass species of drier areas, can be more important, at least in certain seasons. For greylaggeese, Anser anser

official agencies.Therein lies the real problem of environmental planning.
The Regional plan was submitted to Govt. of Maharashtra in early 1985.While the Board was in session, the Govt.created the post of Additional Collector to handle the administrative machinery of the region.As the Competent Authority designated by the Regional Plan, the Additional Collector has the responsibility of enforcing the recommendations of the Plan which has the force of law under the provisions of Maharashtra Regional and Town-Planning Act 1966, till the government makes a final decision about the Plan.Till to-day Govt. of Maharashtra has not made up its mind about accepting or rejecting the Plan.The provisions contained in the Plan thus continue to have the force of law.
The character of the plateau today remains what in essence it was before the building boom started.Most of the big estates carved out of agricultural and other open land on the plateau have their lay-outs and building plans in suspension, though a few, taking advantage of the discretionary powers handed over to the Chairman of the Board, are reported to have wriggled out some concessions.The powerful building lobby is reported to be busy among the highest political levels trying to abolish the post of the Competent Authority and to see that while accepting the Plan vital modifications are brought in to benefit builders and developers.The local environmental groups appear to be in a limbo.They will have to rise to the occasion once again if the government succumbs to the pressures of the building lobbyand the ecology of the plateau is once again in jeopardy.

Introduction
This study compares the foodhabits of barheaded geese in the Keoladeo National Park to those of other wetlands in the region.Yearlyand seasonal differences in goose foodhabits are examined in the Keoladeo National Park for both greylag and barheaded geese.
Because geese digest only about 25% of the cellulose in their food (Buchsbaum et al. 1986), faecal analysis is an adequate method for estimating food habits.The fact that geese do not have to be killed to examine stomach contents insures that the population can be resampled Reference Govt. of MaharashtlCl Town Planning Dept.1985: Regional Plan for Mahabaleshwar-Panchgani Region 1984Region -2001 10.54081/JES.001/05 over time.

Study Sites
This study was largely conducted in the Keoladeo National Park near Bharatpur, Rajasthan, 50 km west of Agra (27°13' N 77°32' E).This park lies in the floodplain of the Gambhir and Banganga Rivers in a natural depression.Water level is regulated by a floodgate near the Ajan Bund.
While greylag and barheaded geese overwinter in this park, greylags are typically more numerous.In the winter of 1985-86, thereweremore than 6,000 greylag but only about 500-1000 barheaded geese in the Keoladeo National Park.Goose populations were much lower in the winter of 1986-87there, most likely due to drought conditions in the park.
Three other study areas included Siliserh Lake, and SiIiserh Damnear Sariska in Rajasthan and Tundla, near Agra, in Uttar Pradesh.Less than 100 barheaded geese were observed at each of these three study sites on the single visit in March 1986.

Goose Dropping Collection and Analysis
Food habits information was collected everymonth during the winter goose grazing season, November 1985-April 1986, in the Keoladeo National Park, Bharatpur, Rajasthan and then again in Decemberl986-January 1987.To serve as a regional comparison, droppings were collected in March 1986 at Siliserh Lake, Siliserh Dam and Tundla.
A good estimate of food habits in a location was ensured by gathering 100 goose droppings over a wide area for both greylag and barheaded geese.Note that greylag droppings were collected only at the Keoladeo National Park.Each sample of 100 droppings was cleaned of debris, mixed and then blended in a mixer.The faecal material was washed through a 0.1 mm mesh screen for about 5 minutes (Scott and Dahl 1980).Pressurized water was helpful for the cleaning procedure.The cleaned material was then either dried in an oven at 72°C or immediately made into slides (Middleton and van der Valk 1987).
To prepare the slides, a small amount of faecal material wasplaced on the slide and heated on an alcohol burner in Hertwig's solution to clear stains not removed in the washing process.The material was spread evenly over the slide, boiled in Hertwig's mounting medium and covered with a 22 x 50 mm slide cover during the final heating (Baumgartner and Martin 1939).
Aset of reference slides wasprepared fromknown plant material.After chopping the plant, the plant material was processedin the same manner as the faecal material.Referenceslides enabled identification of the plant fragments through microscopic structures such as trichomes, stomates, and silica cells.
To read the slide, starting at the upper left hand comer, 3 or more fragments were identified in a microscope fielduntil 50 fieldshad been read.Fields with less than 3 identifiable fragments were skipped (Scott and Dahl 1980).For each sample from an area, 5 slides were read and averaged.More than one area was averaged for each month in the Keoladeo National Park.The other sites, Siliserh Lake,Siliserh Damand Tundla are from only one goose flock in one area in March 1986.

Seasonal Variation
In the Keoladeo National Park, Paspalum distichum constitutes nearlyhalf(45%) of the diets of barheaded geese in December1985-April 1986 (Table 1).Crops such as wheat, peas and grams are important in certain months.In January 1986, wheat constituted 65%of the diet, but, as it is not eaten in later months, made up only 16%ofthe total seasonal diet.Peas grew in importance in the diet through the season until April, just before barheaded goose migration, when peas made up 72%of the diet.Overall, peas made up 42% of the diets of barheaded geese in the Keoladeo National Park (Table 1).

Yearly variation
Barheaded goose diet was much different in winter 1986-87 than in the previous winter.Paspalum distichum made up 72% of the January 1987 diet but only 11% of the January 1986 diet.Wheat was less important in January 1987 (17%) than January'1986 (65%)./pomoeaaquatica was 7% of the diet in January 1987, whereas in January 1986, only 1% was of Ipomoea aquatica (Table 1).

Regional Variation
As an example of how much regional variation appears in this brief study, while barheaded goose diet in March 1986 in the Keoladeo National Park included 50% of Paspalum distichum (Table 1), in other areassuch asTundla,SiIiserhLake,andSiliserhDam,barheadedgoose diet was dominated by Cynodon dactylon (75%), a ciryland grass.In addition, the percentage of crop plants eaten by barheaded geese varied greatly in different regions (0-48%; Table 1).In areas outside of the Keoladeo National Park, wheat was found in smaIl amounts in the Siliserh Lake sample (3%), but wheat was not found in theSiliserh Dam or Tundla samples.While crop plants may be present at other times, this study did not find significant crop plant usage in the diets of bar headed geese at these sites in March 1986.

Greylag Geese Seasonal Variation
Greylag geese had large differences in seasonal food habits during the winter of 1985-86.Paspalum distichum was the most important food overall (68%) just as it was for barheaded geese (Table 2).The usage of Paspalum distichum by greylag geese increased during the season, but earlier in winter 1985-86, seeds of Nymphaea nouchali and Oryza rufipogon were important.These constituted only 13% and 10% respectively of the total diet, because their usage dropped off sharply as the winter season progressed.No crop specie5 were found in greylag goose droppings'in any month (Table 2).

Yearly Variation
A comparison of December 1986 and the wetter December 1985 shows large differences in food habits for greylag geese.Eleocharis palustris made up 42% of the diet in December 1986, but was not a paft of the diet in December 1985.Likewise, Ipomoea aquatica was 29% of the diet in December 1986, but only 1% of the December 1985 diet.Paspalum distichum was 14% of the Decemberl986 diet, but was 31 %ofDecember 1985 diet.Food habits apparently vary not only regionally, but also between years at a single site.Conclusions 1. Goose feeding is very variable depending on the nature of the wetland and the surrounding area, weather, season of the year and the array of potential food plants.2. We cannot predict where geese will feed based on food availability because goose flocks feed on a wide variety of plants in the same region during the same time period.3. Caution should be used in making general statements about what geese eat based on too little information.Overall food habits of grey lags and barheads could be described only with long-term, multi-regional studies with special attention given to seasonal variation of diet within a study site.4. What geese need to eat cannot be inferred from what they do eat.
Food requirements of geese would have to be determined by studies of migration, overwintering and reproductive nutrition.5. Barheaded geese eat mostly non-agricultural plants in this study, while greylag geese eat only wild, wetland plants.