Avian species and diversity on the campus of Universitas Sumatera Utara, Medan City

Universitas Sumatera Utara (USU) is strategically situated for conducting investigations into the biodiversity of flora and fauna, serving as a source of genetic resources for educational purposes. USU, as a green campus, plays a multifunctional role in determining, protecting, and disseminating information regarding biodiversity, including avian diversity, to support environmentally sustainable development. The USU campus area essentially serves as an urban zone with a focus on species diversity and conservation, making it a key aspect of management. This study aims to identify bird species and diversity on the campus and analyze the diversity index and evenness of bird species on the campus. The methods employed involve direct observations using the line transect method combined with the point count method. We documented a total of 36 bird species, encompassing 22 families. The Avian Diversity Index value on the campus was calculated as 3.117, and the Avian Evenness Index was 0.870. The most prevalent families were Columbidae and Cisticolidae, constituting 3.8% of the total.


Introduction
Birds represent the largest class after fish, encompassing a wide array of taxa and comprising an estimated 9,700 identified species.Within ecosystems, birds traverse various trophic levels in food webs, spanning from herbivores and intermediate consumers to apex predators.Alongside fellow organisms, birds play a vital role in upholding equilibrium between prey and predator populations.A multitude of bird species serve as essential pollinators in the reproductive cycle of flowering plants.From an ecological standpoint, birds meet the criteria of environmental bioindicators, rendering them invaluable tools for gauging the overall health of an ecosystem [1].
Birds are wild creatures that can be easily encountered in nearly every type of vegetation.Their habitats can span various ecosystems, ranging from natural to artificial ones.This widespread distribution makes birds one of Indonesia's potential sources of biodiversity richness.Beyond their role in ecosystem balance, birds can serve as indicators of environmental changes.Indonesia boasts a notably high diversity of bird species.The richness of bird species in a given region is supported by the diversity of habitats present.For wildlife, habitats function as places for foraging, drinking, resting, and breeding.Based on these functions, IOP Publishing doi:10.1088/1755-1315/1352/1/012074 2 the diversity of bird species is closely related to the diversity of habitat types, as well as the various functions of each habitat type within urban forests.The conservation of birds can be sustained through species-specific efforts informed by studies or research on these creatures, including aspects such as population, habitat, and environmental influences.The presence of a species in a particular area depends on the availability of food resources and suitable habitat conditions.
Changes in the environment can lead to shifts in ecological conditions, often marked by a decline in biodiversity potential, particularly among sensitive wildlife like birds, which are highly responsive to environmental changes [2].Various bird species can be found in different types of habitats, including forests (both primary and secondary), agroforests, plantations, and open areas like residential yards.Forests offer facilities for birds to nest, rest, breed, and forage.However, it's crucial to pay attention to the composition of species found in each land use type, as this composition is closely related to their roles in ecosystem balance [3].
The selection of bird habitats and species composition is greatly influenced by the diverse range of habitats, including wetlands, rainforests, human settlements, agricultural lands, and rivers [4].Additionally, environmental factors such as sunlight, temperature, vegetation, and rainfall will impact the species richness present in a particular area [5,6].The level of bird species diversity varies from one location to another, depending on habitat conditions, fragmentation, and the extent of human disturbance through hunting and bird trade.Urban bird fauna is generally less diverse compared to forested habitats.The scarcity of urban bird fauna is largely attributed to the tendency of shooting birds using firearms or slingshots by uninformed individuals who are unaware of the ecological benefits of birds to the environment.Ecological reasons for bird scarcity include a shortage of suitable food sources for productive plant species, limited availability of insects that can utilize non-native trees, leading to decreased food resources for insectivorous birds.Birds are still perceived by some communities as income sources or hunting targets, and certain individuals find enjoyment in shooting birds even without consuming them.Furthermore, it is stated that the decline in bird diversity is due to illegal hunting, both domestic and international trade, habitat loss, especially for foraging and nesting grounds [7,8].
Universitas Sumatera Utara (USU) is a public university located in Medan, North Sumatra, established on August 20, 1952.USU spans an area of 133.5 hectares, with 100 hectares dedicated to the academic zone, characterized by the implementation of an environmentally friendly living practice through the concept of a green campus.Recognized as a University for Industry, USU is strategically positioned to conduct investigations into the biodiversity of its flora and fauna, serving as a genetic resource for life within the realms of education and research.As one of the largest state universities in Sumatra, USU, operating as a green campus, serves multiple functions including conservation, protection, and dissemination of information about biodiversity, encompassing avian diversity, all in support of sustainable development with an environmental perspective [9].

Research location
This research was conducted at the Universitas Sumatera Utara, Medan, Indonesia.Observations were made through the first gate into the fourth gate and explored the entire area.

Data collection
Data collection for bird species at the location was conducted through direct observations.Direct observations were carried out using a combination of the line transect method and the Point Count method.This approach involved drawing a line transect along the observation path at entrances 1, 2, 3 and 4 of the USU campus, which was then divided into 10 counting points spaced 150 meters apart.This division was based on the presence or absence of bird species in the area.The selection of observation points was determined by identifying areas with potential encounters, considering the vegetation cover at those points.The Point Count method involved slow walking, pausing, and observing at a single point for 20 minutes using binoculars.The number and species of birds encountered at each location were recorded using a counter and writing tools.Additionally, bird photographs were taken at specific points using a digital camera.Observations were conducted in the morning from 07:00 to 10:00 AM and in the afternoon from 03:00 to 06:00 PM.Other parameters recorded included the encounter time, weather conditions, and any indirect signs such as calls, feathers, nests, silhouettes and droppings.

Avian species identification
Avian species identification was conducted directly in the field and further verified in the Laboratory of Animal Ecology and Systematics.This verification involved examining the obtained bird species photos using the bird identification book by MacKinnon et al [10].

Data analysis
The results of bird species diversity observations are presented in the form of tables and graphs.The calculation of species diversity utilizes the Shannon-Wiener diversity index [11].The Shannon-Wiener formula is as follows: = High diversity Species evenness is calculated using the following formula [11]: Where : E = Species evenness index H' = Shannon-Wiener's diversity index ln = Natural logarithm S = Number of individuals of each species

Results and discussion
Our study revealed a total of 36 avian species in the area of Universitas Sumatera Utara campus, consisting of 10 orders and 22 families.Location 1 recorded 18 bird species, location 2 had 20 bird species, location 3 had 27 bird species, and location 4 had 33 bird species.Among these, 15 bird species were most frequently encountered across all four locations, including the species known as Scaly-breasted Munia (Lonchura punctulata).Additionally, species like the Barn Owl (Tyto alba) were found only once during the survey.Birds can adapt to human presence by altering their behavior, such as foraging behaviors involving scavenging for food scraps in trash areas.This adaptation encompasses adjustments in both behavioral interactions with their environment and interactions with humans [6].This can also be observed in the presence of various bird species along paths frequented by human activities within the Universitas Sumatera Utara campus area.Birds found in urban areas are often encountered at all times and are not challenging to locate.Residential areas also offer food sources for birds due to the presence of plants maintained by residents [2].Based on the research by Saputra et al. [7], the bird frequently encountered in residential areas is L. punctulata.This bird commonly feeds on seeds and fruits planted by the residents, and it has become accustomed to the environment created by the surrounding community.In the four surveyed locations, several avian species classified as migratory were also observed, including the Bentet loreng (Lanius tigrinus), Layang-layang batu (Hirundo javanica) and shikra (Accipiter badius).Notably, the shikra stands out as a raptor species renowned for its collective migratory behavior.Certain raptor species are documented to undertake migratory journeys in cohesive groups, utilizing consistent migration routes [8].The Shannon-Wiener Diversity Index serves as a quantified measure indicating the extent of biodiversity within a given community.The resultant calculations for both the Shannon-Wiener Diversity Index (H') and Evenness Index (J) of avian species across the Universitas Sumatera Utara campus locale are tabulated in Table 2.According to data, the avian within the Universitas Sumatera Utara campus area is categorized as high.The data analysis yielded an H' value of 3.117, with an Evenness Index (E) of 0.870.The diversity index ranges from 0 to 3, reflecting the level of species diversity at a specific location.The elevated value of the diversity index across the campus can be attributed to factors such as the abundance of diverse tree species providing perching, shelter, and sustenance for the bird species within the campus area [11,12].diversity value indicates a complex community where a high species richness is plausible, although higher dominance might be observed.This suggests that only a few species dominate the habitat, while various interactions are likely to take place [13].In line with this, Ayat and Tata [14] highlighted that bird communities often exhibit dominance by specific types, characterized by relatively high abundance, while the majority of other species exhibit lower abundance.
Various tree species such as Samanea saman (Rain Tree), Adenanthera pavonina (Saga), Mimusops elengi (Spanish Cherry), Barringtonia asiatica (Sea Poison Tree) and Tamarindus indica (Tamarind) are scattered around the campus and serve as foraging spots for several bird species like the Burung madu kelapa (Anthreptes malacensis) and Burung madu sriganti (Cinnyris jugularis) within the research area.Trees with tall canopies, including Swietenia macrophylla (Mahogany) and Pterocarpus indicus (Angsana), are perch sites for raptors like the Shikra (A. badius).A cluster of oil palm trees (Elaeis spp) along the entrance path of gate 4 is frequented by species like the Merbah cerukcuk (Pycnonotus goiavier) for foraging.This is because the understory vegetation beneath plantations such as cocoa, rubber, and oil palm provides sustenance and refuge for several bird species, thereby enhancing diversity and abundance [13].Furthermore, various water sources around the campus are utilized by water-associated species like the Kuntul kerbau (Bubulcus ibis) and Kuntul kecil (Egretta garzetta) for food seeking.
Trees, as vital habitat components, fulfill multiple roles for birds, serving as covers for nesting, resting, and shelter.The high diversity of vegetation at a location can also act as a source of sustenance, particularly through fruits.Tree vegetation further provides habitat for other organisms, such as insects, which in turn serve as food for birds.The diversity of bird species is influenced by factors such as epiphyte abundance, fruit availability, forest floor openness, and tree composition [12].The considerable interaction between the campus environment and avian life suggests that, for birds to coexist with other species, certain bird types exhibit opportunistic and generalist behaviors in utilizing available resources [15].

Conclusion
Over the course of the four-week research period, a total of 494 bird individuals from 36 different species and 22 families were recorded within the campus of Universitas Sumatera Utara.The calculated Avian Diversity Index value for the campus is 3.117 and the Avian Evenness Index value is 0.870.The order with the highest number of species was Passeriformes, accounting for a total of 20 bird species.The species that dominated the campus of Universitas Sumatera Utara was L. punctulata, with a count of 68 individuals.

Figure 1 .
Figure 1.Map of research location.

Figure 2 .
Figure 2. Schemmatic drawing of transect line and implementation of point count method.

Table 1 .
Records of avian species in the USU campus area.

Table 2 .
Ecological analysis of avian diversity in the USU Campus area.