Using an interactive map-based PDF, students learn key concepts related to biodiversity while developing data-analysis and critical-thinking skills. The Bird Island lesson provides students with experience in translating geospatial data into bar graphs, then interpreting these graphs to compare biodiversity across ecoregions on a fictional island. When the lesson is extended to include real data for Puerto Rico, students can explore distributions of selected bird species based on environmental attributes, making connections between each species’ adaptations, habitat requirements, and distribution across the island. This introductory lesson provides a jumping-off point for field and Web-based biodiversity investigations.

When we began creating biodiversity-related investigations for middle and high school students (, we decided to introduce key terms by having students explore relevant data-driven issues and discover the need for appropriate language to discuss their findings. The aim is for students to be able to describe the biodiversity of a region using terms such as species richness, abundance, and evenness and to categorize individual species using terms such as specialist, generalist, endemic, endangered, and invasive. Rather than memorizing such terms, students learn them in the context of exploring and describing patterns of data. They conduct this data exploration using an interactive geospatial PDF map (GeoPDF). Created using ArcGIS geographic information system (GIS) software, the PDF map allows students to turn data layers on and off just as they would in Google Earth or a GIS. However, a GeoPDF has the advantage that it can be used on any computer without any specialized software, simply using the freely available Adobe Reader program.

Geospatial technologies, such as GeoPDFs, GIS, and Google Earth, enable teachers to teach ecological principles in fundamentally new ways, building student interest and skill through active engagement and critical thinking using geographic representations. Students are naturally drawn to looking at landscapes and interpreting features through analysis of shape and form. Given the chance to manipulate spatial data, students revel in deciphering mysteries, exploring scientific explanations, and developing explanations for patterns revealed by the data available. Students learn from what they are seeing, and often they are drawn into wanting to know more.

Using GeoPDFs that we have created, students manipulate map layers to analyze distributions of bird populations across ecoregions on an island. In the engagement activity, fictional data are used so that key terms can be clearly illustrated and students can productively wrestle with ways to describe species distributions. After constructing the meanings of key concepts, students apply these concepts in using real data to explore the distributions of bird populations in Puerto Rico.

Learning Objectives

Through these activities, students will be able to

  • Identify and use appropriate terms to describe biodiversity.

  • Interpret geospatial data to reach conclusions about ecological influences on species distributions.

  • Create graphs using spatial data.

  • Use various metrics to assess and compare biodiversity.


  • Bird Populations on Bird Island GeoPDF file

  • Puerto Rico Bird Populations GeoPDF file

  • Newsprint

  • Tape

  • A-V Equipment:

    • ∘ LCD Projector

    • ∘ Screen or Whiteboard

  • Computers

  • Acrobat Reader

The two GeoPDFs are available for free download along with other lesson-related resources ( Ideally, students will be able to manipulate the maps directly in a computer lab or on classroom laptops. Alternatively, the class can work through these exercises collectively, with the teacher projecting the maps and conducting the manipulations.

Guided-Inquiry Investigation 1: Fictional Bird Island

Layers portrayed in the fictional Bird Island GeoPDF include ecoregion boundaries and names, locations of bird observations, and species-specific counts at each site (Figure 1).

Figure 1.

Using the Bird Island GeoPDF, students manipulate layers representing ecoregion delineations and sightings of six imaginary bird species.

Figure 1.

Using the Bird Island GeoPDF, students manipulate layers representing ecoregion delineations and sightings of six imaginary bird species.

The teacher displays the GeoPDF using an LCD projector and explains that it represents scientists’ observations of six imaginary bird species on a remote oceanic island. Each point indicates a sampling site at which one or more individuals of the species were seen. Initially, only the observation locations are turned on, in order to elicit student comments on what the map might represent.

When students have recognized that these are locations in which the bird species listed in the legend were observed, the teacher turns on the layer denoting counts of each species at each location. Students are then asked how they might make sense of these data. Typically they begin with the idea of calculating the number of birds observed for each species but don’t yet begin to talk about how the birds are distributed across the island. Once the ecoregion layer is revealed, students begin to see opportunities for comparing the presence or absence of species across regions. The class discusses the steps required in order to represent and compare bird diversity within and across the island’s six ecoregions. Example questions, answers, and responses include the following:

  1. What would you need to do in order to compare the diversity of bird species on Bird Island?

    • Potential student answers: Divide Bird Island into smaller areas to make it easier to compare different types of ecosystems on the island. Count the number of birds within each of these areas.

      • Teacher response: Scientists have classified all land on Earth into “ecoregions,” each of which represents a distinct assemblage of species and natural communities.

  2. Looking at the map, how many ecoregions are on Bird Island?

    • Six ecoregions

  3. How could you compare one ecoregion to another?

    • Potential student answer: Count the number of species in each ecoregion.

      • Teacher response: This is referred to as “species richness.”

    • Potential student answer: Count the number of individuals within each species in an ecoregion.

      • Teacher response: This is referred to as “species abundance.”

To begin this process, the class divides into groups and each is assigned an ecoregion. Collaborating within groups, students create large bar graphs on newsprint to represent the number of individuals in each species seen within their assigned ecoregion. After viewing these graphs on the classroom walls, the ensuing discussion focuses on comparing and contrasting species distributions across ecoregions (Figure 2). In two regions, each species shows similar abundance, or number of individuals per species. Only one region shows all six species – this region represents the highest species richness. The teacher facilitates student development of operational definitions for these concepts and reinforces or refines those definitions throughout the lesson. Example questions, answers, and responses include these:

Figure 2.

Class discussion focuses on comparing and contrasting species distribution across the six ecoregions on Bird Island.

Figure 2.

Class discussion focuses on comparing and contrasting species distribution across the six ecoregions on Bird Island.

  1. What similarities or differences do you notice among ecoregions?

    • Potential student answer: Ecoregions A and F have a similar number of individuals within each species.

      • Teacher response: Do you remember what this is called? We describe the number of individuals as “abundance.”

        Class discussion: Ecoregions A and F show relatively equal species abundance. The other ecoregions show greater variability in species abundance.

    • Potential student answer: Ecoregion D has the highest number of species.

      • Teacher response: Do you remember what this is called? We describe this as “high species richness.”

        Class discussion: Species richness varies from four to six species in these ecoregions.

  2. Why might some ecoregions have more species than others?

    • Potential student answers:

      • Habitat preferences or needs

      • Availability of food resources

      • Size of each ecoregion

      • Terrain of each ecoregion

      • Extent to which each ecoregion has been altered by urban development, agriculture, or other human influences

As the class further analyzes the graphs, discussions shift to focusing on why species richness is higher in some ecoregions than in others. Clearly the regions are not uniform. Some are larger than others. Although definitive explanations are impossible with the limited data provided, students may speculate about differences in topography and other land features that create habitats suitable for some species but not others. To follow up on these ideas, each group graphs the distribution of a single species across the six ecoregions. When these six graphs are displayed, it becomes evident that one species is isolated within a single region while others are more widely dispersed. This leads to discussion such as the following:

  1. What similarities or differences do you notice among bird species on Bird Island?

    • Potential student answer: Woodstock wilsoni is present only in Ecoregion D.

      Teacher response: Do you know what a species is called when it is found in only one ecoregion? An “endemic species.”

  2. Why might Woodstock wilsoni be endemic to Ecocregion D?

    • Potential student answers:

      • Habitat preferences or needs – it lives only along the shoreline.

      • Availability of food resources – it might depend on a species of fish that lives along the shoreline of Ecoregion D.

At this point, terms describing individual species characteristics can be pursued, for example noting that some species are generalists whereas others have highly specialized habitat requirements. Follow-up discussions can focus on ecological and political implications such as how scientists and policy makers might use such terms to describe the distribution of an endangered species or the ecological value of a particular ecoregion. A teacher might pose questions such as the following:

  1. How might these terms help a scientist describe an ecological setting?

  2. Why might such vocabulary be important to someone in charge of managing invasive species in a park or natural area?

  3. How might such terms be used by a policy maker or politician?

Using the fictional Bird Island, students cannot determine why some species are widespread and others are limited in range, or correlate individual species with their habitat preferences. In order to make this sort of analysis possible, we created a similar GeoPDF that represents real data for selected bird species on the island of Puerto Rico.

Guided-Inquiry Investigation 2: Bird Island Puerto Rico

Using bird sighting data available through the Cornell Lab of Ornithology’s eBird citizen science project (, we created a GeoPDF that portrays the distributions of 11 bird species in Puerto Rico. We added GIS layers representing various environmental attributes, including ecoregion boundaries, topography, and land use. With the resulting GeoPDF, students can explore ecoregion attributes and address the question of why these bird species show different distributions across the island. In doing so, the class can address additional concepts, including habitat, niche, adaptation, generalist versus specialist species, invasive species, endangered species, human impact, and the role of citizen science in data collection.

The bird species were selected to represent a variety of population distributions. One species, the Elfin Woods Warbler (Dendroica angelae), is endemic to Puerto Rico, and its small populations live exclusively in highland forests on this island. By contrast, species such as the White-tailed Tropicbird (Phaethon lepturus) and Brown Noddy (Anous stolidus) are seen only along the coastlines; and others, including the Puerto Rican Tody (Todus mexicanus), Zenaida Dove (Zenaida aurita), and Bananaquit (Coereba flaveola), are widely distributed across the island. Another species portrayed on this map is the invasive Eurasian Collared Dove (Streptopelia decaocto). Native to Asia and Europe, this species spread rapidly across the continental United States and Puerto Rico after its introduction to the Bahamas in the mid-1970s.

To compare species distributions with various environmental features, students manipulate map layers delineating land use, elevation, contours, ecoregion boundaries, and locations of rivers, cities, and roads. Displaying only the Elfin Woods Warbler layer, for example, students see that this species clusters in only a few locations (Figure 3). Turning on the elevation layer makes it evident that these locations consist of the island’s highest regions (Figure 4).

Figure 3.

Distribution of the Elfin Woods Warbler in Puerto Rico, as indicated by sightings contributed to the eBird citizen science project (

Figure 3.

Distribution of the Elfin Woods Warbler in Puerto Rico, as indicated by sightings contributed to the eBird citizen science project (

Figure 4.

Distribution of the Elfin Woods Warbler, superimposed on elevation.

Figure 4.

Distribution of the Elfin Woods Warbler, superimposed on elevation.

To investigate why some species are widespread whereas others are confined to fewer locations, students can investigate the habitat requirements of selected species. Useful sources of this information include the Cornell Lab of Ornithology’s Neotropical Birds ( and All About Birds ( websites. Information about ecoregions is provided by WWF ( Guiding questions for students might include these:

  • What ecoregion does your bird inhabit?

  • What are the biological characteristics or adaptations of the bird that make it suited to its habitat?

  • What are the major characteristics of this ecoregion?

  • Why does your bird live in this ecoregion? (What resources, habitat, etc. appear to make this a suitable “home” for this bird?)

Teacher Perspectives & Reflections

Over the past several years, teachers participating in Crossing Boundaries have implemented the Bird Island and Puerto Rico lessons in middle through high school and Advanced Placement biology and environmental science courses. At the lower grade levels, teachers provide greater scaffolding for graph making and interpretation, for example leading the class through construction of an example graph before asking them to produce one on their own. Those without access to a computer lab have projected the GeoPDF for the class to analyze collectively rather than asking each student group to do so on their own. On the other end of the technology spectrum, teachers whose classes will use ArcGIS later in the year report that learning to use the GIS software is simplified when students have already become familiar with the concept of geospatial analysis through the Bird Island exercise.

Most commonly these activities serve to introduce the concepts of species diversity, adaptations, and habitat, but one teacher used them instead to assess student understanding at the completion of his unit on biodiversity. A middle school teacher assessed learning outcomes by asking her students to select which ecoregion would likely be most attractive to ecotourists and create a brochure highlighting its features in terms of diversity of bird life.

Two teachers used the GeoPDF analysis as a springboard introducing factors that might influence biodiversity before the students launched into field investigations in which they compared biodiversity among various types of habitat in their community. One noted that when her students were measuring plant species diversity at various sites in a local woodland, she overheard them appropriately applying vocabulary they had learned in the Bird Island exercise.

A high school teacher assigned Puerto Rican bird species to her students and instructed them to respond to these questions above and create podcasts to present their findings. Reflecting on her implementation of the Bird Island and Puerto Rico exercises, this teacher stated, “This lesson is interactive as well as cooperative. It promotes group discussion and student thinking when comparing the regions. The technology is great because it is easy to use, and something a little different for the students to use. They enjoyed clicking the different birds species to see the different distributions.”

Another teacher used the Puerto Rico Bird Island extension in his high school biology classes to introduce students to spatial data analysis and ecological principles including niche, habitat, and biodiversity. His students explored the bird-sighting data and made connections between species distribution and environmental factors such as topography and location of roads, cities, rivers, and coastlines. Students researched one of the highlighted bird species and answered ecological questions using data provided in the GeoPDF and related reference sources. Reflecting on these activities, this teacher stated, “This is an excellent opportunity to demonstrate the power of geospatial analysis. The PDF is simple to use and does not require much preparation or manipulation of the layers. Students analyze real spatial data, focusing on key ecological concepts and learning about GIS technology without the possible time constraints of using fully functional GIS software.”

We have heard from teachers that using these GeoPDFs is straightforward and yields rich outcomes, enabling students to focus on ecological concepts without being distracted by technology. A common comment is that graphing practice is always useful, but especially so in this applied context. One high school biology teacher noted that although his students have constructed many bar graphs over the years, this was the first time they had created them to address targeted questions in which they needed to interpret spatial data. Making and comparing graphs based on geospatial data gives students the opportunity to visualize and quantify ideas that are not readily apparent merely by looking at maps. In discussing their findings, students experience the need for terms to represent and communicate about various aspects of biodiversity, learning through experience why specialized terminology is needed in science.


Through guided exploration of data portrayed in maps and graphs, students can develop data analysis skills and use critical thinking to build understanding of key concepts related to biodiversity. The Bird Island and Bird Life in Puerto Rico lessons provide students with experience in using maps as a research tool. Through interpreting geospatial data, translating these data into simple bar graphs, and making comparisons across ecoregions, students derive the meaning of various ecological concepts related to biodiversity. Using a GeoPDF makes this type of exercise relatively simple, requiring no specialized software or GIS skills.

In the Puerto Rico activity, students explore distributions of selected bird species in relation to environmental attributes and see links among adaptations, habitat requirements, and distribution of each species across the island. Through these exercises, the vocabulary of biodiversity comes to life and acquires meaning beyond memorization. For classes with time to delve further into ecological studies, this basic introduction provides a jumping-off point from which students can pose questions and conduct biodiversity investigations in the field or using online data available through eBird or other natural-history databases.


We are grateful for the collaborative spirit of all the Crossing Boundaries teachers who have helped to shape these exercises, piloted them with their students, and determined how best to assess the multiple dimensions of intended student learning outcomes. Courtney Wilson took the lead in writing the Bird Island lesson and creating the geospatial PDFs. This material is based on work supported by the National Science Foundation under grant no. 0833675. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.